Add win32com.gen_py (#12901)

stubs/pywin32/win32com/__init__.pyi

@@ -1,9 +1,9 @@
-from _typeshed import Incomplete
+from collections.abc import MutableSequence
+
+from . import gen_py as gen_py
 
 __gen_path__: str
-__build_path__: Incomplete
+__build_path__: str | None
 
 def SetupEnvironment() -> None: ...
-def __PackageSupportBuildPath__(package_path) -> None: ...
-
-gen_py: Incomplete
+def __PackageSupportBuildPath__(package_path: MutableSequence[str]) -> None: ...