Reformat tools/codegen with black
To do https://github.com/pytorch/pytorch/pull/75972 in a lint free
way I need to reformat all the imports (which are now incorrectly
indented). This is a pain to do manually, so I plan to ask black to
do it for me. But the files are not black compliant. So first reformat
everything with black.
This commit was generated with:
```
black tools/codegen
```
Signed-off-by: Edward Z. Yang <ezyangfb.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/76015
Approved by: https://github.com/bdhirsh
