message: Add a helpful comment
diff: @@ -224,6 +224,8 @@ class RoomViewStore extends Store {
  err: err,
  });
  let msg = err.message ? err.message : JSON.stringify(err);
  + // XXX: We are relying on the error message returned by browsers here.
  + // This isn't great, but it does generalize the error being shown to users.
  if (msg && msg.startsWith("CORS request rejected")) {
  msg = _t("There was an error joining the room");
  }
  