Do not ignore `torch/__init__.pyi` (#42958)
Summary:
Delete abovementioned from .gitignore as the file is gone since https://github.com/pytorch/pytorch/issues/42908 and no longer should be autogenerated.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/42958
Reviewed By: seemethere
Differential Revision: D23094391
Pulled By: malfet
fbshipit-source-id: af303477301ae89d6f283e34d7aeddeda7a9260f
