Replace modified with last_modified_at (#930)

Fixes #929

_layouts/single.html

@@ -21,7 +21,7 @@ layout: default
     {% if page.title %}<meta itemprop="headline" content="{{ page.title | markdownify | strip_html | strip_newlines | escape_once }}">{% endif %}
     {% if page.excerpt %}<meta itemprop="description" content="{{ page.excerpt | markdownify | strip_html | strip_newlines | escape_once }}">{% endif %}
     {% if page.date %}<meta itemprop="datePublished" content="{{ page.date | date: "%B %d, %Y" }}">{% endif %}
-    {% if page.modified %}<meta itemprop="dateModified" content="{{ page.modified | date: "%B %d, %Y" }}">{% endif %}
+    {% if page.last_modified_at %}<meta itemprop="dateModified" content="{{ page.last_modified_at | date: "%B %d, %Y" }}">{% endif %}
 
     <div class="page__inner-wrap">
       {% unless page.header.overlay_color or page.header.overlay_image %}
@@ -43,8 +43,8 @@ layout: default
           <h4 class="page__meta-title">{{ site.data.ui-text[site.locale].meta_label }}</h4>
         {% endif %}
         {% include page__taxonomy.html %}
-        {% if page.modified %}
+        {% if page.last_modified_at %}
-          <p class="page__date"><strong><i class="fa fa-fw fa-calendar" aria-hidden="true"></i> {{ site.data.ui-text[site.locale].date_label | default: "Updated:" }}</strong> <time datetime="{{ page.modified | date: "%Y-%m-%d" }}">{{ page.modified | date: "%B %d, %Y" }}</time></p>
+          <p class="page__date"><strong><i class="fa fa-fw fa-calendar" aria-hidden="true"></i> {{ site.data.ui-text[site.locale].date_label | default: "Updated:" }}</strong> <time datetime="{{ page.last_modified_at | date: "%Y-%m-%d" }}">{{ page.last_modified_at | date: "%B %d, %Y" }}</time></p>
         {% elsif page.date %}
           <p class="page__date"><strong><i class="fa fa-fw fa-calendar" aria-hidden="true"></i> {{ site.data.ui-text[site.locale].date_label | default: "Updated:" }}</strong> <time datetime="{{ page.date | date_to_xmlschema }}">{{ page.date | date: "%B %d, %Y" }}</time></p>
         {% endif %}

_layouts/splash.html

@@ -13,7 +13,7 @@ layout: default
     {% if page.title %}<meta itemprop="headline" content="{{ page.title | markdownify | strip_html | strip_newlines | escape_once }}">{% endif %}
     {% if page.excerpt %}<meta itemprop="description" content="{{ page.excerpt | markdownify | strip_html | strip_newlines | escape_once }}">{% endif %}
     {% if page.date %}<meta itemprop="datePublished" content="{{ page.date | date: "%B %d, %Y" }}">{% endif %}
-    {% if page.modified %}<meta itemprop="dateModified" content="{{ page.modified | date: "%B %d, %Y" }}">{% endif %}
+    {% if page.last_modified_at %}<meta itemprop="dateModified" content="{{ page.last_modified_at | date: "%B %d, %Y" }}">{% endif %}
 
     <section class="page__content" itemprop="text">
       {{ content }}

docs/_docs/01-quick-start-guide.md

@@ -2,7 +2,7 @@
 title: "Quick-Start Guide"
 permalink: /docs/quick-start-guide/
 excerpt: "How to quickly install and setup Minimal Mistakes for use with GitHub Pages."
-modified: 2016-11-03T10:01:43-04:00
+last_modified_at: 2016-11-03T10:01:43-04:00
 redirect_from:
   - /theme-setup/
 ---

docs/_docs/02-structure.md

@@ -2,7 +2,7 @@
 title: "Structure"
 permalink: /docs/structure/
 excerpt: "How the theme is organized and what all of the files are for."
-modified: 2016-10-06T22:39:43-04:00
+last_modified_at: 2016-10-06T22:39:43-04:00
 ---
 
 Nothing clever here :wink:. Layouts, data files, and includes are all placed in their default locations. Stylesheets and scripts in `assets`, and a few development related files in the project's root directory.

docs/_docs/03-installation.md

@@ -2,7 +2,7 @@
 title: "Installation"
 permalink: /docs/installation/
 excerpt: "Instructions for installing the theme for new and existing Jekyll based sites."
-modified: 2016-11-03T10:13:32-04:00
+last_modified_at: 2016-11-03T10:13:32-04:00
 ---
 
 ## Install the Theme

docs/_docs/04-upgrading.md

@@ -2,7 +2,7 @@
 title: "Upgrading"
 permalink: /docs/upgrading/
 excerpt: "Instructions and suggestions for upgrading the theme."
-modified: 2016-11-03T10:16:34-04:00
+last_modified_at: 2016-11-03T10:16:34-04:00
 ---
 
 If you're using the Ruby Gem version of the theme upgrading is fairly painless.

docs/_docs/05-configuration.md

@@ -2,7 +2,7 @@
 title: "Configuration"
 permalink: /docs/configuration/
 excerpt: "Settings for configuring and customizing the theme."
-modified: 2016-11-29T08:44:22-05:00
+last_modified_at: 2016-11-29T08:44:22-05:00
 ---
 
 Settings that affect your entire site can be changed in [Jekyll's configuration file](https://jekyllrb.com/docs/configuration/): `_config.yml`, found in the root of your project. If you don't have this file you'll need to copy or create one using the theme's [default `_config.yml`](https://github.com/mmistakes/minimal-mistakes/blob/master/_config.yml) as a base.

docs/_docs/06-overriding-theme-defaults.md

@@ -2,7 +2,7 @@
 title: "Overriding Theme Defaults"
 permalink: /docs/overriding-theme-defaults/
 excerpt: "Instructions on how to customize the theme's default set of layouts, includes, and stylesheets when using the Ruby Gem version."
-modified: 2016-11-03T10:49:48-04:00
+last_modified_at: 2016-11-03T10:49:48-04:00
 ---
 
 When installing the theme as a Ruby Gem its layouts, includes, stylesheets, and other assets are all bundled in the `gem`. Meaning they're not easily visible in your project.

docs/_docs/07-navigation.md

@@ -2,7 +2,7 @@
 title: "Navigation"
 permalink: /docs/navigation/
 excerpt: "Instructions on how to customize the main navigation and enabling breadcrumb links."
-modified: 2016-11-03T10:50:03-04:00
+last_modified_at: 2016-11-03T10:50:03-04:00
 ---
 
 ## Masthead

docs/_docs/08-ui-text.md

@@ -2,7 +2,7 @@
 title: "UI Text"
 permalink: /docs/ui-text/
 excerpt: "Text for customizing various user interface elements found in the theme."
-modified: 2017-02-14T14:13:24-05:00
+last_modified_at: 2017-02-14T14:13:24-05:00
 ---
 
 Text for various UI elements, `_layouts`, and `_includes` have all been grouped together as a set of translation keys. This is by no means a full-on i18n solution, but it does help make customizing things a bit easier.

docs/_docs/09-authors.md

@@ -2,7 +2,7 @@
 title: "Authors"
 permalink: /docs/authors/
 excerpt: "Instructions and settings for working with multiple site authors."
-modified: 2016-11-03T10:55:15-04:00
+last_modified_at: 2016-11-03T10:55:15-04:00
 ---
 
 Sites that may have content authored from various individuals can be accommodated by using [data files](https://jekyllrb.com/docs/datafiles/).

docs/_docs/10-layouts.md

@@ -7,7 +7,7 @@ single_layout_gallery:
     alt: "single layout with header example"
   - image_path: /assets/images/mm-layout-single-meta.png
     alt: "single layout with comments and related posts"
-modified: 2017-02-24T15:23:34-05:00
+last_modified_at: 2017-02-24T15:23:34-05:00
 ---
 
 {% include toc icon="columns" title="Included Layouts" %}

docs/_docs/11-posts.md

@@ -2,7 +2,7 @@
 title: "Working with Posts"
 permalink: /docs/posts/
 excerpt: "Suggestions and Front Matter defaults for working with posts."
-modified: 2016-11-03T11:12:40-04:00
+last_modified_at: 2016-11-03T11:12:40-04:00
 ---
 
 Posts are stored in the `_posts` directory and named according to the `YEAR-MONTH-DAY-title.MARKUP` format as per [the usual](https://jekyllrb.com/docs/posts/).

docs/_docs/12-pages.md

@@ -2,7 +2,7 @@
 title: "Working with Pages"
 permalink: /docs/pages/
 excerpt: "Suggestions and Front Matter defaults for working with pages."
-modified: 2016-11-03T11:13:12-04:00
+last_modified_at: 2016-11-03T11:13:12-04:00
 ---
 
 To better organize all of your pages you can centralize them into a single location similar to posts and collections.

docs/_docs/13-collections.md

@@ -2,7 +2,7 @@
 title: "Working with Collections"
 permalink: /docs/collections/
 excerpt: "Suggestions and Front Matter defaults for working with collections."
-modified: 2016-11-03T11:13:38-04:00
+last_modified_at: 2016-11-03T11:13:38-04:00
 ---
 
 Collections like posts and pages work as you'd expect. If you're new to them be sure to read [Jekyll's documentation](https://jekyllrb.com/docs/collections/).

docs/_docs/14-helpers.md

@@ -30,7 +30,7 @@ feature_row:
   - image_path: /assets/images/unsplash-gallery-image-3-th.jpg
     title: "Placeholder 3"
     excerpt: "This is some sample content that goes here with **Markdown** formatting."
-modified: 2016-11-15T12:11:48-05:00
+last_modified_at: 2016-11-15T12:11:48-05:00
 ---
 
 {% include toc icon="gears" title="Helpers" %}

docs/_docs/15-utility-classes.md

@@ -2,7 +2,7 @@
 title: "Utility Classes"
 permalink: /docs/utility-classes/
 excerpt: "CSS classes for aligning text/image, styling buttons and notices, and more."
-modified: 2016-11-03T11:32:25-04:00
+last_modified_at: 2016-11-03T11:32:25-04:00
 ---
 
 {% include toc icon="gears" title="Utility Classes" %}

docs/_docs/16-stylesheets.md

@@ -2,7 +2,7 @@
 title: "Stylesheets"
 permalink: /docs/stylesheets/
 excerpt: "Instructions for customizing and building the theme's stylesheets."
-modified: 2016-11-03T11:34:42-04:00
+last_modified_at: 2016-11-03T11:34:42-04:00
 ---
 
 The theme's `assets/css/main.css` file is built from several SCSS partials located in [`_sass/`](https://github.com/mmistakes/minimal-mistakes/tree/master/_sass) and is structured as follows:

docs/_docs/17-javascript.md

@@ -2,7 +2,7 @@
 title: "JavaScript"
 permalink: /docs/javascript/
 excerpt: "Instructions for customizing and building the theme's scripts."
-modified: 2016-11-03T11:35:42-04:00
+last_modified_at: 2016-11-03T11:35:42-04:00
 ---
 
 The theme's [`assets/js/main.min.js`] script is built from several vendor, jQuery plugins, and other scripts found in [`assets/js/`](https://github.com/mmistakes/minimal-mistakes/tree/master/assets/js).

docs/_docs/18-history.md

@@ -4,7 +4,7 @@ permalink: /docs/history/
 excerpt: "Change log of enhancements and bug fixes made to the theme."
 sidebar:
   nav: docs
-modified: 2017-03-27T08:24:24-04:00
+last_modified_at: 2017-03-27T08:24:24-04:00
 ---
 
 ## Unreleased

docs/_docs/19-contributing.md

@@ -2,7 +2,7 @@
 title: "Contributing"
 permalink: /docs/contributing/
 excerpt: "How you can contribute to make this theme better."
-modified: 2017-03-22T09:51:05-04:00
+last_modified_at: 2017-03-22T09:51:05-04:00
 ---
 
 Having trouble working with the theme? Found a typo in the documentation? Interested in adding a feature or [fixing a bug](https://github.com/mmistakes/minimal-mistakes/issues)? Then by all means [submit an issue](https://github.com/mmistakes/minimal-mistakes/issues/new) or [pull request](https://help.github.com/articles/using-pull-requests/). If this is your first pull request, it may be helpful to read up on the [GitHub Flow](https://guides.github.com/introduction/flow/) first.

docs/_docs/20-docs-2-2.md

@@ -2,7 +2,7 @@
 title: "2.2 Documentation"
 permalink: /docs/docs-2-2/
 excerpt: "Setup and installation instructions for Minimal Mistakes 2.2 (deprecated)."
-modified: 2016-04-13T15:54:02-04:00
+last_modified_at: 2016-04-13T15:54:02-04:00
 ---
 
 {% include toc %}

docs/_docs/21-license.md

@@ -2,7 +2,7 @@
 title: "License"
 permalink: /docs/license/
 excerpt: "License for Minimal Mistakes Jekyll Theme."
-modified: 2016-04-13T15:05:12-04:00
+last_modified_at: 2016-04-13T15:05:12-04:00
 ---
 
 The MIT License (MIT)

docs/_layouts/single.html

@@ -21,7 +21,7 @@ layout: default
     {% if page.title %}<meta itemprop="headline" content="{{ page.title | markdownify | strip_html | strip_newlines | escape_once }}">{% endif %}
     {% if page.excerpt %}<meta itemprop="description" content="{{ page.excerpt | markdownify | strip_html | strip_newlines | escape_once }}">{% endif %}
     {% if page.date %}<meta itemprop="datePublished" content="{{ page.date | date: "%B %d, %Y" }}">{% endif %}
-    {% if page.modified %}<meta itemprop="dateModified" content="{{ page.modified | date: "%B %d, %Y" }}">{% endif %}
+    {% if page.last_modified_at %}<meta itemprop="dateModified" content="{{ page.last_modified_at | date: "%B %d, %Y" }}">{% endif %}
 
     <div class="page__inner-wrap">
       {% unless page.header.overlay_color or page.header.overlay_image %}
@@ -43,8 +43,8 @@ layout: default
           <h4 class="page__meta-title">{{ site.data.ui-text[site.locale].meta_label }}</h4>
         {% endif %}
         {% include page__taxonomy.html %}
-        {% if page.modified %}
+        {% if page.last_modified_at %}
-          <p class="page__date"><strong><i class="fa fa-fw fa-calendar" aria-hidden="true"></i> {{ site.data.ui-text[site.locale].date_label | default: "Updated:" }}</strong> <time datetime="{{ page.modified | date: "%Y-%m-%d" }}">{{ page.modified | date: "%B %d, %Y" }}</time></p>
+          <p class="page__date"><strong><i class="fa fa-fw fa-calendar" aria-hidden="true"></i> {{ site.data.ui-text[site.locale].date_label | default: "Updated:" }}</strong> <time datetime="{{ page.last_modified_at | date: "%Y-%m-%d" }}">{{ page.last_modified_at | date: "%B %d, %Y" }}</time></p>
         {% elsif page.date %}
           <p class="page__date"><strong><i class="fa fa-fw fa-calendar" aria-hidden="true"></i> {{ site.data.ui-text[site.locale].date_label | default: "Updated:" }}</strong> <time datetime="{{ page.date | date_to_xmlschema }}">{{ page.date | date: "%B %d, %Y" }}</time></p>
         {% endif %}

docs/_layouts/splash.html

@@ -13,7 +13,7 @@ layout: default
     {% if page.title %}<meta itemprop="headline" content="{{ page.title | markdownify | strip_html | strip_newlines | escape_once }}">{% endif %}
     {% if page.excerpt %}<meta itemprop="description" content="{{ page.excerpt | markdownify | strip_html | strip_newlines | escape_once }}">{% endif %}
     {% if page.date %}<meta itemprop="datePublished" content="{{ page.date | date: "%B %d, %Y" }}">{% endif %}
-    {% if page.modified %}<meta itemprop="dateModified" content="{{ page.modified | date: "%B %d, %Y" }}">{% endif %}
+    {% if page.last_modified_at %}<meta itemprop="dateModified" content="{{ page.last_modified_at | date: "%B %d, %Y" }}">{% endif %}
 
     <section class="page__content" itemprop="text">
       {{ content }}

docs/_pages/about.md

@@ -12,7 +12,7 @@ layouts_gallery:
   - url: /assets/images/mm-layout-archive.png
     image_path: /assets/images/mm-layout-archive.png
     alt: "archive layout example"
-modified: 2017-02-14T14:28:13-05:00
+last_modified_at: 2017-02-14T14:28:13-05:00
 ---
 
 Minimal Mistakes is a flexible two-column Jekyll theme. Perfect for hosting your personal site, blog, or portfolio on GitHub or self-hosting on your own server. As the name implies --- styling is purposely minimalistic to be enhanced and customized by you :smile:.

docs/_pages/terms.md

@@ -1,7 +1,7 @@
 ---
 permalink: /terms/
 title: "Terms and Privacy Policy"
-modified: 2016-11-03T11:57:46-04:00
+last_modified_at: 2016-11-03T11:57:46-04:00
 ---
 
 {% include toc %}

docs/_posts/2010-01-07-post-modified.md

@@ -1,6 +1,6 @@
 ---
 title: "Post: Modified Date"
-modified: 2016-03-09T16:20:02-05:00
+last_modified_at: 2016-03-09T16:20:02-05:00
 categories:
   - Post Formats
 tags:

docs/_posts/2012-03-15-layout-header-overlay-image.md

@@ -11,7 +11,7 @@ tags:
   - edge case
   - image
   - layout
-modified: 2016-11-03T11:45:09-04:00
+last_modified_at: 2016-11-03T11:45:09-04:00
 ---
 
 This post should display a **header with an overlay image**, if the theme supports it.

docs/_posts/2013-08-16-markup-syntax-highlighting.md

@@ -1,7 +1,7 @@
 ---
 title: "Markup: Syntax Highlighting"
 excerpt: "Post displaying the various ways of highlighting code in Markdown."
-modified: 2016-09-09T09:55:10-04:00
+last_modified_at: 2016-09-09T09:55:10-04:00
 header:
   teaser: "assets/images/markup-syntax-highlighting-teaser.jpg"
 tags: 

docs/_posts/2016-09-21-gemified-theme-alpha.md

@@ -1,6 +1,6 @@
 ---
 title:  "Gemified Theme -- Alpha Release"
-modified: 2016-11-03T11:46:00-04:00
+last_modified_at: 2016-11-03T11:46:00-04:00
 categories: 
   - Jekyll
 tags:

docs/_posts/2016-10-06-gemified-theme-beta.md

@@ -1,6 +1,6 @@
 ---
 title:  "Gemified Theme -- Beta Release"
-modified: 2016-11-03T11:45:04-04:00
+last_modified_at: 2016-11-03T11:45:04-04:00
 categories: 
   - Jekyll
 tags:

test/_pages/terms.md

@@ -1,7 +1,7 @@
 ---
 permalink: /terms/
 title: "Terms and Privacy Policy"
-modified: 2016-06-06
+last_modified_at: 2016-06-06
 ---
 
 {% include base_path %}

test/_posts/2010-01-07-post-modified.md

@@ -1,6 +1,6 @@
 ---
 title: "Post: Modified Date"
-modified: 2016-03-09T16:20:02-05:00
+last_modified_at: 2016-03-09T16:20:02-05:00
 categories:
   - Post Formats
 tags:

test/_posts/2012-03-15-layout-header-overlay-image.md

@@ -11,7 +11,7 @@ tags:
   - edge case
   - image
   - layout
-modified: 2016-05-02T11:39:01-04:00
+last_modified_at: 2016-05-02T11:39:01-04:00
 ---
 
 {% include base_path %}

test/_posts/2013-08-16-markup-syntax-highlighting.md

@@ -1,7 +1,7 @@
 ---
 title: "Markup: Syntax Highlighting"
 excerpt: "Post displaying the various ways of highlighting code in Markdown."
-modified: 2016-09-09T09:55:10-04:00
+last_modified_at: 2016-09-09T09:55:10-04:00
 header:
   teaser: "assets/images/markup-syntax-highlighting-teaser.jpg"
 tags: