message: support joining with a room alias for rest session
diff: @@ -37,8 +37,8 @@ module.exports = class RestSession {
  });
  }
  - async join(roomId) {
  - const {room_id} = await this._post(`/rooms/${roomId}/join`);
  + async join(roomIdOrAlias) {
  + const {room_id} = await this._post(`/join/${encodeURIComponent(roomIdOrAlias)}`);
  return new RestRoom(this, room_id);
  }
  