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

Conflicts:
- `app/controllers/activitypub/collections_controller.rb`:
  Conflict caused because we have additional code to make sure pinned
  local-only toots don't get rendered on the ActivityPub endpoints.
  Ported upstream changes.

app/serializers/rest/account_featured_tag_serializer.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+class REST::AccountFeaturedTagSerializer < ActiveModel::Serializer
+  include RoutingHelper
+
+  attributes :id, :name, :url
+
+  def id
+    object.tag.id.to_s
+  end
+
+  def name
+    "##{object.name}"
+  end
+
+  def url
+    short_account_tag_url(object.account, object.tag)
+  end
+end