Fix trivial typos in torch.cuda._utils (#16026)
Summary:
Trivial typo fixings.
Maybe the indefinite article "an" is needed before each "specified index" but I'm not perfectly sure.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/16026
Differential Revision: D13709499
Pulled By: ezyang
fbshipit-source-id: 698b000bb8aa063afd81db6e67046456a439b2ce
