Add: fep-e232引用仕様 (#725)

* Add: fep-e232引用仕様

* Fix test

app/serializers/activitypub/note_serializer.rb

@@ -140,7 +140,19 @@ class ActivityPub::NoteSerializer < ActivityPub::Serializer
   end
 
   def virtual_tags
-    object.active_mentions.to_a.sort_by(&:id) + object.tags + object.emojis
+    object.active_mentions.to_a.sort_by(&:id) + object.tags + object.emojis + virtual_tags_of_quote
+  end
+
+  def virtual_tags_of_quote
+    return [] unless object.quote?
+
+    [
+      {
+        type: 'Link',
+        mediaType: 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"',
+        href: quote_uri,
+      },
+    ]
   end
 
   def atom_uri