Fix typing of RegexHighlighter.highlights using ClassVar

[SudheerKovvuru]

Type of changes

• Bug fix
• New feature
• Documentation / docstrings
• Tests
• Other

AI?

• AI was used to generate this PR

AI generated PRs may be accepted, but only if @willmcgugan has responded on an issue or discussion.

Checklist

• I've run the latest black with default args on new code.
• I've updated CHANGELOG.md and CONTRIBUTORS.md where appropriate (see note about typos above).
• I've added tests for new code.
• I accept that @willmcgugan may be pedantic in the code review.

Description

Please describe your changes here.
This PR updates the typing of RegexHighlighter.highlights to explicitly mark it as a class variable using ClassVar and an immutable tuple.

The change is limited to typing and does not alter runtime behavior.

Note: Some rendering-related tests fail locally on Windows (Python 3.11), which appears to be environment-specific and unrelated to this change.

Important: Link to an issue or discussion regarding these changes.
Fixes #3888

[willmcgugan]

But it is a list. And while it does coincidentally work with a pattern, I can think of no good reason to pre-compile it. the re library will cache compilation anyway.

[SudheerKovvuru]

Thanks for the clarification, that makes sense.
I’ve updated the type to ClassVar[tuple[str, ...]] to better reflect actual usage and avoid implying pre-compilation.

[SudheerKovvuru]

Thanks for the review!
Since the issue has now been resolved and merged upstream via #3939, I’m closing this PR to avoid duplication.
Appreciate the clarification and feedback.