feat(Guild): setVanityCode

Co-Authored-By: Chino-chan <93425627+Tungchaphet@users.noreply.github.com>

#533

typings/index.d.ts

@@ -1441,6 +1441,7 @@ export class Guild extends AnonymousGuild {
     reason?: string,
   ): Promise<Guild>;
   public setWidgetSettings(settings: GuildWidgetSettingsData, reason?: string): Promise<Guild>;
+  public setVanityCode(code?: string): Promise<Vanity>;
   public toJSON(): unknown;
 }