Grammar patch 1 (.md) (#41599)
Summary:
A minor spell check!
I have gone through a dozen of .md files to fix the typos.
zou3519 take a look!
Pull Request resolved: https://github.com/pytorch/pytorch/pull/41599
Reviewed By: ezyang
Differential Revision: D22601629
Pulled By: zou3519
fbshipit-source-id: 68d8f77ad18edc1e77874f778b7dadee04b393ef
