message: also support deserializing at-room-pill when transferring editor state
diff: @@ -376,6 +376,8 @@ export class PartCreator {
  return this.plain(part.text);
  case "newline":
  return this.newline();
  + case "at-room-pill":
  + return this.atRoomPill(part.text);
  case "pill-candidate":
  return this.pillCandidate(part.text);
  case "room-pill":
  