Change how hashtags are normalized (#18795)

* Change how hashtags are normalized

* Fix tests

app/serializers/rest/featured_tag_serializer.rb

@@ -12,4 +12,8 @@ class REST::FeaturedTagSerializer < ActiveModel::Serializer
   def url
     short_account_tag_url(object.account, object.tag)
   end
+
+  def name
+    object.display_name
+  end
 end

app/serializers/rest/tag_serializer.rb

@@ -8,4 +8,8 @@ class REST::TagSerializer < ActiveModel::Serializer
   def url
     tag_url(object)
   end
+
+  def name
+    object.display_name
+  end
 end