Update comment and add region tags (GoogleCloudPlatform#1285)

I want to use a docwidget in the docs to display the part of app.yaml that needs to be configured.

Author: navinger

endpoints/getting-started/app.yaml

@@ -5,8 +5,10 @@ entrypoint: gunicorn -b :$PORT main:app
 runtime_config:
   python_version: 3
 
+# [START configuration]
 endpoints_api_service:
   # The following values are to be replaced by information from the output of
-  # 'gcloud endpoints services deploy openapi.yaml' command.
-  name: ENDPOINTS SERVICE-NAME
-  config_id: ENDPOINTS CONFIG-ID
+  # 'gcloud endpoints services deploy openapi-appengine.yaml' command.
+  name: ENDPOINTS-SERVICE-NAME
+  config_id: ENDPOINTS-CONFIG-ID
+  # [END configuration]