[doc] update distributed optimizer doc (#58084)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/58084
update the doc for distributed optimizer with TorchScript support.
Test Plan: Imported from OSS
Reviewed By: rohan-varma
Differential Revision: D28363971
Pulled By: wanchaol
fbshipit-source-id: df9d2acc1bbb2292d683d2231e1349b8d3946c8f
