Merge branch 'mjang-doc-api-routes' into 'master'

Identify how to list RESTful API endpoints

See merge request gitlab-org/gitlab!29436

doc/development/rake_tasks.md

@@ -232,6 +232,9 @@ To see the full list of API routes, you can run:
 bundle exec rake grape:path_helpers
 ```
 
+The generated list includes a full list of API endpoints and functional
+RESTful API verbs.
+
 For the Rails controllers, run:
 
 ```shell