docs: fix docstring signature of torch.{onnx,utils} (#54662)
Summary:
fixes https://github.com/pytorch/pytorch/issues/50018
fixes https://github.com/pytorch/pytorch/issues/50017
https://11811000-65600975-gh.circle-artifacts.com/0/docs/onnx.html#functions
https://11811000-65600975-gh.circle-artifacts.com/0/docs/mobile_optimizer.html
Pull Request resolved: https://github.com/pytorch/pytorch/pull/54662
Reviewed By: ailzhang
Differential Revision: D27328485
Pulled By: zou3519
fbshipit-source-id: e658542072ba633b9c309145fc5182edf895d0a6
