fix: update references of Re-generate to Regenerate

[Adi-ty]

What?

Closes #439

Updates all instances of the hyphenated "Re-generate" to "Regenerate".

Why?

This ensures consistent spelling and terminology across the plugin's user interface, documentation, and test suites.

How?

Performed a global search and replace across the repository to update "Re-generate" to "Regenerate". This includes updates to UI copy, Markdown documentation, and End-to-End test assertions so the testing suite continues to pass.

Changelog Entry

Fixed - Updated UI copy and tests to use "Regenerate" consistently instead of "Re-generate".

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 68.44%. Comparing base (7d98557) to head (8ce7522).
⚠️ Report is 11 commits behind head on develop.

Additional details and impacted files

@@            Coverage Diff             @@
##             develop     #449   +/-   ##
==========================================
  Coverage      68.44%   68.44%           
  Complexity       846      846           
==========================================
  Files             56       56           
  Lines           4095     4095           
==========================================
  Hits            2803     2803           
  Misses          1292     1292           

Flag	Coverage Δ
unit	68.44% <ø> (ø)

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[github-actions]

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Co-authored-by: Adi-ty <iamadisingh@git.wordpress.org>
Co-authored-by: jeffpaul <jeffpaul@git.wordpress.org>

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