Stop showing .api as an API path component in RPC docs (#30160)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/30160
The path torch.distributed.rpc.api is an implementation detail, which
should not be used by applications to import RPC APIs. Instead, all
RPC APIs are exposed directly as torch.distributed.rpc.*. This
commit makes the API doc consistent with the above expectation.
Test Plan: Imported from OSS
Differential Revision: D18616359
Pulled By: mrshenli
fbshipit-source-id: 8207f7d36c24cf55af737c03a27fd1896c231641
