message: Fix some features appearing multiple times
diff: @@ -271,6 +271,7 @@ This means that the old features will still be on the page and don't need to re-
  This marks each as "processed"
  */
  void add(__filebasename, {
  + deduplicate: false,
  init: async () => {
  // `await` kicks it to the next tick, after the other features have checked for 'has-rgh', so they can run once.
  await Promise.resolve();
  