message: Return false if mentions are disabled
diff: @@ -1097,11 +1097,15 @@ IrcHandler.prototype._setMatrixRoomAsInviteOnly = function(room, isInviteOnly) {
  };
  IrcHandler.prototype.invalidateCachingForUserId = function(userId) {
  + if (this._mentionMode === "force-off") {
  + return false;
  + }
  this.nickUserIdMapCache.forEach((mapping, serverChannel) => {
  if (Object.values(mapping).includes(userId)) {
  this.nickUserIdMapCache.delete(serverChannel);
  }
  });
  + return true;
  }
  IrcHandler.prototype._invalidateNickUserIdMap = function(server, channel) {
  