message: add: UnknownSession error code
diff: @@ -17,6 +17,7 @@ export enum DiscordJsonErrorCodes {
  UnknownEmoji,
  UnknownWebhook,
  UnknownWebhookService,
  + UnknownSession = 10020,
  UnknownBan = 10026,
  UnknownSKU,
  UnknownStoreListing,
  