[`pep8-naming`] Fix formatting of `__all__` (`N816`) (#20301)
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## Summary
Noticed this was not escaped when writing a project that parses the
result of `ruff rule --outputformat json`. This is visible here:
<https://docs.astral.sh/ruff/rules/mixed-case-variable-in-global-scope/#why-is-this-bad>
## Test Plan
documentation only
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Co-authored-by: Brent Westbrook <36778786+ntBre@users.noreply.github.com>
