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

Conflicts:
- `app/controllers/api/v1/statuses_controller.rb`:
  Conflict due to upstream adding a new parameter (with_rate_limit),
  too close to glitch-soc's own additional parameter (content_type).
  Added upstream's parameter.
- `app/services/post_status_service.rb`:
  Conflict due to upstream adding a new parameter (rate_limit),
  too close to glitch-soc's own additional parameter (content_type).
  Added upstream's parameter.
- `app/views/settings/preferences/appearance/show.html.haml`:
  Conflict due to us not exposing theme settings here (as we have
  a different flavour/skin menu).
  Took upstream change, while still not exposing theme settings.
- `config/webpack/shared.js`:
  Coding style fixes for a part we have rewritten.
  Discarded upstream changes.

app/serializers/rest/announcement_serializer.rb

@@ -7,6 +7,7 @@ class REST::AnnouncementSerializer < ActiveModel::Serializer
   attribute :read, if: :current_user?
 
   has_many :mentions
+  has_many :statuses
   has_many :tags, serializer: REST::StatusSerializer::TagSerializer
   has_many :emojis, serializer: REST::CustomEmojiSerializer
   has_many :reactions, serializer: REST::ReactionSerializer
@@ -46,4 +47,16 @@ class REST::AnnouncementSerializer < ActiveModel::Serializer
       object.pretty_acct
     end
   end
+
+  class StatusSerializer < ActiveModel::Serializer
+    attributes :id, :url
+
+    def id
+      object.id.to_s
+    end
+
+    def url
+      ActivityPub::TagManager.instance.url_for(object)
+    end
+  end
 end