key-info: add 11.17 notice

people clicking the get started button miss the warning on the homepage

_pages/en_US/key-information.txt

@@ -4,6 +4,11 @@ title: "Key Information"
 
 {% include toc title="Table of Contents" %}
 
+{% capture update-notice %}
+{% include_relative include/3ds-11.17.txt %}
+{% endcapture %}
+<div class="notice--danger">{{ update-notice | markdownify }}</div>
+
 If this is your first time modding a 3DS (or you're unfamiliar with technology), keep reading! Otherwise, if you have prior experience and know what you're doing, continue to [Get Started](get-started).
 {: .notice--info}