Use char-wise width instead of str-width

[dhruvmanila]

Summary

This PR updates various references in the linter to compute the line-width for summing the width of each char in a str instead of computing the width of the str itself.

Refer to #12133 for more details.

fixes: #12130

Test Plan

Add a file with null (\0) character which is zero-width. Run this test case on main to make sure it panics and switch over to this branch to make sure it doesn't panic now.

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

ℹ️ ecosystem check encountered linter errors. (no lint changes; 1 project error)

demisto/content (error)

ruff check --no-cache --exit-zero --ignore RUF9 --output-format concise --preview

warning: The top-level linter settings are deprecated in favour of their counterparts in the `lint` section. Please update the following options in `pyproject.toml`:
  - 'ignore' -> 'lint.ignore'
  - 'select' -> 'lint.select'
  - 'unfixable' -> 'lint.unfixable'
  - 'per-file-ignores' -> 'lint.per-file-ignores'
warning: `PGH001` has been remapped to `S307`.
warning: `PGH002` has been remapped to `G010`.
warning: `PLR1701` has been remapped to `SIM101`.
ruff failed
  Cause: Selection of deprecated rule `E999` is not allowed when preview is enabled.

[codspeed-hq]

CodSpeed Performance Report

Merging #12135 will not alter performance

_{Comparing dhruv/char-wise-width (a8cd872) with main (37f260b)}

Summary

✅ 30 untouched benchmarks

[MichaReiser]

Hmm, why is this considered to be a binary file?

[dhruvmanila]

It contains \0 character. I think I'll just inline the source code of that file as a separate test case to not do this.

[dhruvmanila]

I think it's just the diff tab that renders it like that. The normal GitHub view is as: https://github.com/astral-sh/ruff/blob/dhruv/char-wise-width/crates/ruff_linter/resources/test/fixtures/pycodestyle/E501_4.py