fix include in failing test

Author: InteNs

test/action_controller/json_api/linked_test.rb

@@ -82,7 +82,7 @@ def render_collection_without_include
 
           def render_collection_with_include
             setup_post
-            render json: [@post], adapter: :json_api, include: 'author, comments'
+            render json: [@post], adapter: :json_api, include: 'author,comments'
           end
         end