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

spec/lib/emoji_formatter_spec.rb

@@ -24,7 +24,7 @@ RSpec.describe EmojiFormatter do
       let(:text) { preformat_text(':coolcat: Beep boop') }
 
       it 'converts the shortcode to an image tag' do
-        is_expected.to match(/<img draggable="false" class="emojione custom-emoji" alt=":coolcat:"/)
+        is_expected.to match(/<img rel="emoji" draggable="false" width="16" height="16" class="emojione custom-emoji" alt=":coolcat:"/)
       end
     end
 
@@ -32,7 +32,7 @@ RSpec.describe EmojiFormatter do
       let(:text) { preformat_text('Beep :coolcat: boop') }
 
       it 'converts the shortcode to an image tag' do
-        is_expected.to match(/Beep <img draggable="false" class="emojione custom-emoji" alt=":coolcat:"/)
+        is_expected.to match(/Beep <img rel="emoji" draggable="false" width="16" height="16" class="emojione custom-emoji" alt=":coolcat:"/)
       end
     end
 
@@ -48,7 +48,7 @@ RSpec.describe EmojiFormatter do
       let(:text) { preformat_text('Beep boop :coolcat:') }
 
       it 'converts the shortcode to an image tag' do
-        is_expected.to match(/boop <img draggable="false" class="emojione custom-emoji" alt=":coolcat:"/)
+        is_expected.to match(/boop <img rel="emoji" draggable="false" width="16" height="16" class="emojione custom-emoji" alt=":coolcat:"/)
       end
     end
   end