Add missing lint

Author: srujzs

fixtures/_webdevSoundSmoke/web/main.dart

@@ -5,6 +5,8 @@
 import 'dart:async';
 import 'dart:convert';
 import 'dart:developer';
+// TODO: https://github.com/dart-lang/webdev/issues/2508
+// ignore: deprecated_member_use
 import 'dart:html';
 
 void main() {