Fix invalid-name regression for class attributes in subclasses

[jacobtylerwalls]

Type of Changes

	Type
✓	🐛 Bug fix

Description

Fixes #9765

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.84%. Comparing base (52955ba) to head (872b60c).
Report is 143 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #9772   +/-   ##
=======================================
  Coverage   95.84%   95.84%           
=======================================
  Files         174      174           
  Lines       18878    18878           
=======================================
  Hits        18094    18094           
  Misses        784      784           

Files with missing lines	Coverage Δ
pylint/checkers/base/name_checker/checker.py	98.63% <100.00%> (ø)

[github-actions]

🤖 Effect of this PR on checked open source code: 🤖

Effect on music21:
The following messages are no longer emitted:

1. invalid-name:
   Class attribute name "registerOutputSubformatExtensions" doesn't conform to '([A-Za-z_][A-Za-z0-9_]{2,30}|(__.__))$' pattern*
   https://github.com/cuthbertLab/music21/blob/204e9d0b9eec2f2d6ff8d8d3b13c41f912050604/music21/converter/subConverters.py#L355
2. invalid-name:
   Class attribute name "registerOutputSubformatExtensions" doesn't conform to '([A-Za-z_][A-Za-z0-9_]{2,30}|(__.__))$' pattern*
   https://github.com/cuthbertLab/music21/blob/204e9d0b9eec2f2d6ff8d8d3b13c41f912050604/music21/converter/subConverters.py#L411
3. invalid-name:
   Class attribute name "registerOutputSubformatExtensions" doesn't conform to '([A-Za-z_][A-Za-z0-9_]{2,30}|(__.__))$' pattern*
   https://github.com/cuthbertLab/music21/blob/204e9d0b9eec2f2d6ff8d8d3b13c41f912050604/music21/converter/subConverters.py#L834

This comment was generated for commit 872b60c