Generate mypy hints for torch.Tag, add a couple of pointwise ops (#106910)
Replace https://github.com/pytorch/pytorch/pull/106739, since i had a bad CLA commit.
- adds clone, and convert_element_dtype to pointwise
- adds codegen for mypy hints of torch.Tag and removes existing ignores for them
Pull Request resolved: https://github.com/pytorch/pytorch/pull/106910
Approved by: https://github.com/mlazos
