Fix doc s/#/. for class method name

Author: bf4

lib/action_controller/serialization.rb

@@ -22,13 +22,13 @@ def serialization_scope
     # Deprecated
     def get_serializer(resource)
       fail ActiveModel::Serializer::Error, "ActionController::Serialization##{__method__} has been removed. "\
-        "Please use ActiveSupport::Serializer#build instead"
+        "Please use ActiveSupport::Serializer.build instead"
     end
 
     # Deprecated
     def use_adapter?
       fail ActiveModel::Serializer::Error, "ActionController::Serialization##{__method__} has been removed. "\
-        "Please use ActiveSupport::Serializer#build instead"
+        "Please use ActiveSupport::Serializer.build instead"
     end
 
     [:_render_option_json, :_render_with_renderer_json].each do |renderer_method|