docs: fix allcontributors and add helenamerk as a contributor for code

[allcontributors]

Adds @helenamerk as a contributor for code.

This was requested by JoshuaKGoldberg in this comment

[skip ci]

[github-actions]

PR Compliance Checks

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Issue Reference

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[codecov]

Codecov Report

Merging #139 (1cffa0c) into main (fe1ef21) will not change coverage.
The diff coverage is n/a.

❗ Current head 1cffa0c differs from pull request most recent head 682fe23. Consider uploading reports for the commit 682fe23 to get more accurate results

@@          Coverage Diff          @@
##            main    #139   +/-   ##
=====================================
  Coverage   2.94%   2.94%           
=====================================
  Files         13      13           
  Lines        849     849           
=====================================
  Hits          25      25           
  Misses       824     824           

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