Add Learn section to sidebar

Move videos, Pro Git book, and external links to Learn section.

Will require the book CI to rerun to update the section of the site the
book is in.

Author: jvns

content/doc/ext/_index.html

@@ -1,5 +1,5 @@
 ---
-section: "documentation"
+section: "learn"
 subsection: "external-links"
 title: "Git - External Links"
 url: /doc/ext.html

content/videos/_index.html

@@ -1,5 +1,5 @@
 ---
-section: "documentation"
+section: "learn"
 subsection: "videos"
 title: "Git - Videos"
 url: /videos.html

layouts/partials/sidebar.html

@@ -17,14 +17,16 @@
           {{ end }}
         </ul>
       </li>
+
       <li>
-        <a href="{{ relURL "doc" }}"{{ if (eq $section "documentation") }} class="active"{{ end }}>Documentation</a>
-        <ul {{ if (eq $section "documentation") }}class="expanded"{{ end }}>
+        <a href="{{ relURL "learn" }}"{{ if (eq $section "learn") }} class="active"{{ end }}>Learn</a>
+        <ul {{ if (eq $section "learn") }}class="expanded"{{ end }}>
           <li>
-            <a href="{{ relURL "docs" }}"{{ if or (eq .Params.Subsection "reference") (eq .Params.Subsection "manual") }} class="active"{{ end }}>Reference</a>
+            <a href="{{ relURL "book" }}"{{ if (eq .Params.Subsection "book") }} class="active"{{ end }}>Book</a>
           </li>
+
           <li>
-            <a href="{{ relURL "book" }}"{{ if (eq .Params.Subsection "book") }} class="active"{{ end }}>Book</a>
+            <a href="{{ relURL "cheat-sheet" }}"{{ if (eq .Params.Subsection "cheat-sheet") }} class="active"{{ end }}>Cheat Sheet</a>
           </li>
           <li>
             <a href="{{ relURL "videos" }}"{{ if (eq .Params.Subsection "videos") }} class="active"{{ end }}>Videos</a>
@@ -34,6 +36,14 @@
           </li>
         </ul>
       </li>
+      <li>
+        <a href="{{ relURL "doc" }}"{{ if (eq $section "documentation") }} class="active"{{ end }}>Documentation</a>
+        <ul {{ if (eq $section "documentation") }}class="expanded"{{ end }}>
+          <li>
+            <a href="{{ relURL "docs" }}"{{ if or (eq .Params.Subsection "reference") (eq .Params.Subsection "manual") }} class="active"{{ end }}>Reference</a>
+          </li>
+        </ul>
+      </li>
       <li>
         <a href="{{ relURL "downloads" }}"{{ if (eq $section "downloads") }} class="active"{{ end }}>Downloads</a>
         <ul {{ if (eq $section "downloads") }}class="expanded"{{ end }}>

script/book.rb

@@ -58,7 +58,7 @@ def initialize(edition, language_code)
   def front_matter
     front_matter = {
       "category" => "book",
-      "section" => "documentation",
+      "section" => "learn",
       "subsection" => "book",
       "sidebar" => "book",
       "book" => {