Add RemoteModule to master RPC docs. (#53084)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/53084
Adding RemoteModule to master RPC docs since it is a prototype
feature.
ghstack-source-id: 122816689
Test Plan: waitforbuildbot
Reviewed By: rohan-varma
Differential Revision: D26743372
fbshipit-source-id: 00ce9526291dfb68494e07be3e67d7d9c2686f1b
