Corrected the frontend filename

pkg/api/cloudwatch/metrics.go

@@ -66,7 +66,7 @@ func init() {
 }
 
 // Whenever this list is updated, frontend list should also be updated.
-// Please update the region list in public/app/features/org/datasourceEditCtrl.js
+// Please update the region list in public/app/plugins/datasource/cloudwatch/partials/config.html
 func handleGetRegions(req *cwRequest, c *middleware.Context) {
 	regions := []string{
 		"us-west-2", "us-west-1", "eu-west-1", "eu-central-1", "ap-southeast-1",