Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/74962
This would eliminate the need for build system changes when new .pyi.in files is added
Test Plan: CI
Reviewed By: seemethere
Differential Revision: D35255502
fbshipit-source-id: 9aa84d2fc0f7933293cac4c6588da72a9d649df0
(cherry picked from commit 4931ec5411362692427adca348f409ce4d2a01fc)