Update supported_api_gen.py: remove an invalid escape sequence "\_" using a raw string

[wyattscarpenter]

What changes were proposed in this pull request?

Remove an invalid escape sequence "_" using a raw string instead.

Why are the changes needed?

There is an invalid escape sequence in the code, which is silenced using a noqa comment. Recent python versions warn when parsing such a string, noqa comment or no. (I believe I may have seen this warning when mypy, a python typechecker, visited the code, or something like that.) Using a raw string removes the warning without changing the value of the string in this case. This change also allows us to remove a noqa comment.

Does this PR introduce any user-facing change?

No, except a python warning is silenced.

How was this patch tested?

Manual inspection.

Was this patch authored or co-authored using generative AI tooling?

No.

[HyukjinKwon]

Mind filling the PR description please? https://github.com/apache/spark/blob/master/.github/PULL_REQUEST_TEMPLATE

[wyattscarpenter]

@HyukjinKwon Sure! Sorry for the delay.

[xinrong-meng]

Also we might need a JIRA ticket for the PR proposal. Please JIRA section of https://spark.apache.org/contributing.html

[wyattscarpenter]

Thanks for mentioning!

Reviewing that document, I take this sentence to indicate that this doesn't need a JIRA ticket:

If the change is new, then it usually needs a new JIRA. However, trivial changes, where the what should change is virtually the same as the how it should change do not require a JIRA. Example: Fix typos in Foo scaladoc

[github-actions]

We're closing this PR because it hasn't been updated in a while. This isn't a judgement on the merit of the PR in any way. It's just a way of keeping the PR queue manageable.
If you'd like to revive this PR, please reopen it and ask a committer to remove the Stale tag!

[wyattscarpenter]

This PR is still good and necessary. To whomever is concerned: it should not be marked stale.