Update descriptions for transmitting CUDA tensors (#34888)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/34888
Test Plan: Imported from OSS
Differential Revision: D20491408
Pulled By: mrshenli
fbshipit-source-id: 4ca35ac9edd4c1af4f2bae2cfb0f1f6060658d5c
