Narrow down annotations for fields.Field.formfield (#1739)

Fixes: #1738

Author: WhyNotHugo

django-stubs/db/models/fields/__init__.pyi

@@ -5,6 +5,7 @@ from datetime import date, time, timedelta
 from datetime import datetime as real_datetime
 from typing import Any, ClassVar, Generic, Literal, Protocol, TypeVar, overload
 
+from django import forms
 from django.core import validators  # due to weird mypy.stubtest error
 from django.core.checks import CheckMessage
 from django.core.exceptions import FieldDoesNotExist as FieldDoesNotExist
@@ -202,7 +203,12 @@ class Field(RegisterLookupMixin, Generic[_ST, _GT]):
     def get_db_prep_save(self, value: Any, connection: BaseDatabaseWrapper) -> Any: ...
     def get_internal_type(self) -> str: ...
     # TODO: plugin support
-    def formfield(self, form_class: Any | None = ..., choices_form_class: Any | None = ..., **kwargs: Any) -> Any: ...
+    def formfield(
+        self,
+        form_class: type[forms.Field] | None = ...,
+        choices_form_class: Any | None = ...,
+        **kwargs: Any,
+    ) -> Field: ...
     def save_form_data(self, instance: Model, data: Any) -> None: ...
     def contribute_to_class(self, cls: type[Model], name: str, private_only: bool = ...) -> None: ...
     def to_python(self, value: Any) -> Any: ...