types(schema): allow calling schema.static() with as TStatics

Re: #15780

Author: vkarpov15

test/types/queries.test.ts

@@ -798,3 +798,16 @@ function gh15671() {
     };
   };
 }
+
+async function gh15786() {
+  interface IDoc {
+  }
+
+  interface DocStatics {
+          m1(): void;
+          m2(): void;
+  }
+
+  const schema = new Schema<IDoc, Model<IDoc>, {}, {}, {}, DocStatics>({});
+  schema.static({ m1() {} } as DocStatics);
+}

types/index.d.ts

@@ -542,6 +542,7 @@ declare module 'mongoose' {
 
     /** Adds static "class" methods to Models compiled from this schema. */
     static<K extends keyof TStaticMethods>(name: K, fn: TStaticMethods[K]): this;
+    static(obj: { [F in keyof TStaticMethods]: TStaticMethods[F] }): this;
     static(obj: { [F in keyof TStaticMethods]: TStaticMethods[F] } & { [name: string]: (this: TModelType, ...args: any[]) => any }): this;
     static(name: string, fn: (this: TModelType, ...args: any[]) => any): this;