Update cuda init docstring to improve clarity (#42923)
Summary:
A small clarity improvement to the cuda init docstring
Pull Request resolved: https://github.com/pytorch/pytorch/pull/42923
Reviewed By: zhangguanheng66
Differential Revision: D23080693
Pulled By: mrshenli
fbshipit-source-id: aad5ed9276af3b872c1def76c6175ee30104ccb2
