Remove stray comment from tox.ini

[asottile]

No description provided.

[codecov]

Codecov Report

Merging #5507 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #5507      +/-   ##
==========================================
+ Coverage   96.09%   96.09%   +<.01%     
==========================================
  Files         117      117              
  Lines       25643    25647       +4     
  Branches     2483     2483              
==========================================
+ Hits        24642    24646       +4     
  Misses        696      696              
  Partials      305      305

Impacted Files	Coverage Δ
testing/test_config.py	99.83% <0%> (ø)	⬆️

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