Add comments for adding shape function and linting (#73570)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/73570
Approved by: https://github.com/huiguoo
Test Plan: contbuild & OSS CI, see https://hud.pytorch.org/commit/pytorch/pytorch/6d36bbde7eb2eb0aed448f694338cb49c2ae47f3
Reviewed By: pbelevich
Differential Revision: D35192688
Pulled By: atalman
fbshipit-source-id: b12b80e6a6dd1adaa57a8facb6bb077989faa543
(cherry picked from commit e50478c02592597f12b8490ec5496f76c7d8b8cc)
