[RPC Framework] Update rpc.rst (#57876)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/57876
ghstack-source-id: 128484049
Test Plan: N/A
Reviewed By: pritamdamania87
Differential Revision: D28305719
fbshipit-source-id: cc0d79fb46077a0d1cf6026c373893e7d3b7761e
