2286 pep657 error code ranges in traceback

[Gothingbop]

Type of changes

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

Checklist

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

Description

Pull request for #2286

Replicates some of the functionality in PEP 657 by extracting the col range of the exception and adds the style to the Syntax using Syntax.stylize_range().

Effectively repurposes code found in some private functions in the base traceback module: _get_code_position() and _walk_tb_with_full_positions(). The code would be cleaner if those functions were not private or we were OK with using private functions (raises an error when running the mypy type checking).

I can also abstract the loop into a generator to more closely replicate the _walk_tb_with_full_positions() functionality, but I'm unsure where the best spot for that would be.

Base Python traceback

Rich traceback before

Rich traceback with highlighing

[willmcgugan]

Great in principle.

I think we can improve on the styles a bit. And some of the information present in the ascii version doesn't seem to be styled.

This will also need to handle older Pythons.