message: Better support for Model middleware hooks
  Fixes type SimplePreSerialFn for Model middleware calls
diff: @@ -26,7 +26,7 @@ type TypegooseDoc<T> = T & MongooseDocument;
  type DocumentPreSerialFn<T> = (this: TypegooseDoc<T>, next: HookNextFn) => void;
  type DocumentPreParallelFn<T> = (this: TypegooseDoc<T>, next: HookNextFn, done: PreDoneFn) => void;
  -type SimplePreSerialFn<T> = (next: HookNextFn) => void;
  +type SimplePreSerialFn<T> = (next: HookNextFn, docs?: any[]) => void;
  type SimplePreParallelFn<T> = (next: HookNextFn, done: PreDoneFn) => void;
  type DocumentPostFn<T> = (this: TypegooseDoc<T>, doc: TypegooseDoc<T>, next?: HookNextFn) => void;
  