Merge branch 'main' into glitch-soc/merge-upstream

Conflicts:
- `app/javascript/mastodon/features/compose/components/poll_form.js`:
  glitch-soc change because of having changed the default number of
  available poll options.
  Applied upstream's changes while keeping glitch-soc's default number of
  poll options.
- `public/oops.png`:
  We had a minor graphics change, probably not worth diverging from upstream.
  Took upstream version.

lib/mastodon/version.rb

@@ -17,7 +17,7 @@ module Mastodon
     end
 
     def flags
-      'rc1'
+      'rc2'
     end
 
     def suffix