Remove deprecated system colors

[bartveneman]

fixes #403

[codspeed-hq]

CodSpeed Performance Report

Merging #406 will not alter performance

_{Comparing rm-deprecated-system-colors (034708a) with master (d55d859)}

Summary

✅ 1 untouched benchmarks

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.55%. Comparing base (d55d859) to head (034708a).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #406      +/-   ##
==========================================
- Coverage   99.56%   99.55%   -0.01%     
==========================================
  Files          18       18              
  Lines        2277     2260      -17     
==========================================
- Hits         2267     2250      -17     
  Misses         10       10              

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