[ci skip] Clarify collection caching went EXPLICIT.

Yo dawg, we so explicit if we were a music track, yo' iPhone's Music app would put
an E next to it.

*drops mic*

Author: kaspth

actionview/CHANGELOG.md

@@ -197,16 +197,18 @@
 
     *Ulisses Almeida*
 
-*   Collection rendering automatically caches and fetches multiple partials.
+*   Collection rendering can cache and fetch multiple partials at once.
 
     Collections rendered as:
 
     ```ruby
-    <%= render @notifications %>
-    <%= render partial: 'notifications/notification', collection: @notifications, as: :notification %>
+    <%= render partial: 'notifications/notification', collection: @notifications, as: :notification, cached: true %>
     ```
 
-    will now read several partials from cache at once, if the template starts with a cache call:
+    will read several partials from cache at once. The templates in the collection
+    that haven't been cached already will automatically be written to cache. Works
+    great alongside individual template fragment caching. For instance if the
+    template the collection renders is cached like:
 
     ```ruby
     # notifications/_notification.html.erb
@@ -215,6 +217,9 @@
     <% end %>
     ```
 
+    Then any collection renders shares that cache when attempting to read multiple
+    ones at once.
+
     *Kasper Timm Hansen*
 
 *   Fixed a dependency tracker bug that caused template dependencies not