Add note to torch.save (#40394)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/40394
Test Plan: Imported from OSS
Reviewed By: ailzhang
Differential Revision: D22168181
Pulled By: jamesr66a
fbshipit-source-id: 634104a1c18faf3b6cb0e0f49d3980d671a141f4
