Change RSS feeds (#18356)

* Change RSS feeds

- Use date and time for titles instead of ellipsized text
- Use full content in body, even when there is a content warning
- Use media extensions

* Change feed icons and add width and height attributes to custom emojis

* Fix custom emoji animate on hover breaking

* Fix tests

app/helpers/application_helper.rb

@@ -243,7 +243,7 @@ module ApplicationHelper
     end.values
   end
 
-  def prerender_custom_emojis(html, custom_emojis)
-    EmojiFormatter.new(html, custom_emojis, animate: prefers_autoplay?).to_s
+  def prerender_custom_emojis(html, custom_emojis, other_options = {})
+    EmojiFormatter.new(html, custom_emojis, other_options.merge(animate: prefers_autoplay?)).to_s
   end
 end