add nested Meta inheritance support for forms

mypy_django_plugin/transformers/forms.py

@@ -0,0 +1,9 @@
+from mypy.plugin import ClassDefContext
+from mypy_django_plugin import helpers
+
+
+def make_meta_nested_class_inherit_from_any(ctx: ClassDefContext) -> None:
+    meta_node = helpers.get_nested_meta_node_for_current_class(ctx.cls.info)
+    if meta_node is None:
+        return None
+    meta_node.fallback_to_any = True