fixing python 3.12 syntax warning re invalid escape sequence

[legaltextai]

No description provided.

[mlissner]

Looks good! A couple process things for future PRs:

1. Your commit messages should match our style, which is explained in our dev guide (see number three here: https://github.com/freelawproject/courtlistener/wiki/Getting-Started-Developing-CourtListener/0c803bbbb92eac2fac2f5d79dbff4689f001acc2#guidelines-for-contributions)

2. When you're ready for a review, please request a review from me via the "Reviewers" thing in the sidebar. That way, I'll know it's ready for me.

3. Github has a trick for automatically closing issues that we should use here: https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue#linking-a-pull-request-to-an-issue-using-a-keyword. If you do this, the issue gets automatically closed when your code is merged.

4. You should put this PR on your backlog in the "In Review" section, so you can monitor it.

And I think that's it for process! Thanks for this. It's a relief to finally have these errors going away.