small doc fix (#46599)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/46599
Test Plan: Imported from OSS
Reviewed By: mrshenli
Differential Revision: D24426181
Pulled By: bdhirsh
fbshipit-source-id: d0900d5c43574c80f1bf614824eafd21ba6a9caf
