Minor typo fixes in `_script.py` (#55818)
Summary:
I was reading through this file to get a better understanding of torch.jit.script and just fixed these along the way.
The only functional change is [here](https://github.com/pytorch/pytorch/compare/master...janeyx99:minor-jit-nits?expand=1#diff-c05f6af41a2d9c7ec7a2b15088259fb74763f7d1406da70f324fc6b20af47427R824). Everything else is documentation only.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/55818
Reviewed By: walterddr
Differential Revision: D27718853
Pulled By: janeyx99
fbshipit-source-id: a08f5451a904ef7a440be418f11ec083dd14766d
