feat: Add rtcRegion to GuildManager#create() (#6858)

typings/index.d.ts

@@ -4708,6 +4708,7 @@ export interface PartialChannelData {
   nsfw?: boolean;
   bitrate?: number;
   userLimit?: number;
+  rtcRegion?: string | null;
   permissionOverwrites?: PartialOverwriteData[];
   rateLimitPerUser?: number;
 }