Fix bad region tags (#1263)

Oops!

Author: willum070

samples/map-events/index.ts

@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-// [START maps_map_event]
+// [START maps_map_events]
 const events = [
     'bounds_changed',
     'center_changed',
@@ -73,4 +73,4 @@ function populateTable() {
 }
 
 initMap();
-// [END maps_map_event]
+// [END maps_map_events]