Add type annotations to torch.onnx.* modules (#48782)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/45215
This is a follow up PR of https://github.com/pytorch/pytorch/issues/45258
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48782
Reviewed By: heitorschueroff
Differential Revision: D25304229
Pulled By: ezyang
fbshipit-source-id: b01b21ddbf86f908ca08173e68b81fb25851bc81
