Small documentation changes for RRef and Dist Autograd (#48123)
Summary:
Small wording changes and polishing documentation for:
https://pytorch.org/docs/master/rpc/rref.html
https://pytorch.org/docs/master/rpc/distributed_autograd.html
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48123
Reviewed By: zhangguanheng66
Differential Revision: D25059320
Pulled By: H-Huang
fbshipit-source-id: 7a0be56f062de06483b3bd3a5d617234101862ba
