Tips: add region tags (#696)

* Add terminate region tag

* Massage terminate region tag

Author: Ace Nassri

functions/helloworld/index.js

@@ -38,21 +38,26 @@ exports.helloGET = (req, res) => {
  * @param {Object} req Cloud Function request context.
  * @param {Object} res Cloud Function response context.
  */
+// [START functions_tips_terminate]
 exports.helloHttp = (req, res) => {
   res.send(`Hello ${req.body.name || 'World'}!`);
 };
 // [END functions_helloworld_http]
 
+// [END functions_tips_terminate]
+
 // [START functions_helloworld_background]
 /**
  * Background Cloud Function.
  *
  * @param {object} event The Cloud Functions event.
  * @param {function} callback The callback function.
  */
+// [START functions_tips_terminate]
 exports.helloBackground = (event, callback) => {
   callback(null, `Hello ${event.data.name || 'World'}!`);
 };
+// [END functions_tips_terminate]
 // [END functions_helloworld_background]
 
 // [START functions_helloworld_pubsub]