Add type annotations for torch._C._distributed_c10d module. (#46623)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/46623
Test Plan: Imported from OSS
Reviewed By: malfet
Differential Revision: D24761606
Pulled By: xuzhao9
fbshipit-source-id: 827eaf2502e381ee24d36741c1613b4c08208569
