Add a formatting reference link to the inline comment editor

Summary:
Various text boxes have a documentation link below them.
Make the Differential inline comment box one of them.

Test Plan:
Loaded Differential revision in sandbox. Played around
with inline comments.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T1513

Differential Revision: https://secure.phabricator.com/D3024

src/applications/differential/view/DifferentialInlineCommentEditView.php

@@ -118,6 +118,17 @@ final class DifferentialInlineCommentEditView extends AphrontView {
       'Cancel');
 
     $buttons = implode('', $buttons);
+
+    $formatting = phutil_render_tag(
+      'a',
+      array(
+        'href' => PhabricatorEnv::getDoclink(
+          'article/Remarkup_Reference.html'),
+        'tabindex' => '-1',
+        'target' => '_blank',
+      ),
+      'Formatting Reference');
+
     return javelin_render_tag(
       'div',
       array(
@@ -136,6 +147,7 @@ final class DifferentialInlineCommentEditView extends AphrontView {
         $this->renderChildren().
       '</div>'.
       '<div class="differential-inline-comment-edit-buttons">'.
+        $formatting.
         $buttons.
         '<div style="clear: both;"></div>'.
       '</div>');