Change typo 'momemtum' to 'momentum' (#45045)
Summary:
As the title.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/45045
Reviewed By: mruberry
Differential Revision: D23808563
Pulled By: mrshenli
fbshipit-source-id: ca818377f4c23d67b037c146fef667ab8731961e