message: Update ClientDocumentMixin for v9.245
diff: @@ -275,7 +275,8 @@ export declare class ClientDocumentMixin<T extends foundry.abstract.Document<any
  * (default: `{}`)
  * @param context - Additional context options or dialog positioning options
  * (default: `{}`)
  - * @returns A Promise which resolves to the created Document
  + * @returns A Promise which resolves to the created Document, or null if the dialog was
  + * closed.
  */
  static createDialog<T extends DocumentConstructor>(
  this: T,
  