Disallow non-breaking spaces (#55465)
Summary:
malfet found a couple of these in https://github.com/pytorch/pytorch/issues/55346; this PR removes the rest and adds a lint that prevents them from being accidentally added again in the future. It also removes the `-o` flag added in https://github.com/pytorch/pytorch/issues/53733 (which was unnecessarily hiding context without reducing the number of lines of output), and updates the lint error messages to reflect that the individual line numbers are shown in the logs.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/55465
Test Plan:
The "Lint / quick-checks" job in GitHub Actions should succeed on this PR. To verify that the lint does correctly find and error on non-breaking spaces, checkout ece075195d49c25213c96b9d53fcf7077215f44a and run it locally:
```sh
(! git --no-pager grep -In $'\u00a0' -- . || (echo "The above lines have non-breaking spaces (U+00A0); please convert them to spaces (U+0020)"; false))
```
It should print over a hundred lines of output and exit with status 1.
Reviewed By: janeyx99
Differential Revision: D27622136
Pulled By: samestep
fbshipit-source-id: e7ffd5a9519093e7a0ffdf55e9291f63e21ce841
