Fix pytorch-doc build (#50651)
Summary:
Fixes `docstring of torch.distributed.rpc.RRef.remote:14: WARNING: Field list ends without a blank line; unexpected unindent.` by indenting multiline fieldlist
Pull Request resolved: https://github.com/pytorch/pytorch/pull/50651
Reviewed By: SplitInfinity
Differential Revision: D25935839
Pulled By: malfet
fbshipit-source-id: e2613ae75334d01ab57f4b071cb0fddf80c6bd78
