docs: storage.createBucket: show setting location

lib/storage/index.js

@@ -198,11 +198,14 @@ Storage.prototype.bucket = function(name) {
  * gcs.createBucket('new-bucket', callback);
  *
  * //-
- * // Specify metadata.
+ * // Create a bucket in a specific location and region. <em>See the <a
+ * // href="https://cloud.google.com/storage/docs/json_api/v1/buckets/insert">
+ * // Official JSON API docs</a> for complete details on the `location` option.
+ * // </em>
  * //-
  * var metadata = {
- *   mainPageSuffix: '/unknown/',
- *   maxAgeSeconds: 90
+ *   location: 'US-CENTRAL1',
+ *   storageClass: 'DURABLE_REDUCED_AVAILABILITY'
  * };
  *
  * gcs.createBucket('new-bucket', metadata, callback);