Test HashTable.Resize() directly

[kamikkels]

Just call resize with a negative key to trigger line 300 and actually improve the coverage
See issue #465

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• My code follows the style guidelines of this project
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Comments in areas I changed are up to date
• I have added comments to hard-to-understand areas of my code
• I have made corresponding changes to the README.md

[Copilot]

Pull Request Overview

This PR adds a test case to directly test the HashTable.Resize() method with negative hash values to improve code coverage, specifically targeting line 300 mentioned in issue #465.

• Added a new test method Resize_HandlesNegativeIndexCorrectly() to explicitly call Resize() with a negative hash key

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.22%. Comparing base (6c220ce) to head (25bbd6d).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #533   +/-   ##
=======================================
  Coverage   95.22%   95.22%           
=======================================
  Files         274      274           
  Lines       10910    10910           
  Branches     1535     1535           
=======================================
  Hits        10389    10389           
  Misses        397      397           
  Partials      124      124           

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[siriak]

Looks good, thanks!