Add copyright header to compiled JS

[coliff]

Useful header to show version number, URL and date compiled... e.g.

/*!
 * HTMLHint v1.2.0
 * https://htmlhint.com
 * Built on: 2025-05-31
 * Copyright (c) 2025 HTMLHint
 * Licensed under MIT License
 */

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.59%. Comparing base (95e6a13) to head (98802dc).
Report is 36 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1609      +/-   ##
==========================================
+ Coverage   96.99%   98.59%   +1.60%     
==========================================
  Files           2        2              
  Lines        1628     2066     +438     
  Branches      335      454     +119     
==========================================
+ Hits         1579     2037     +458     
+ Misses         49       29      -20     

Files with missing lines	Coverage Δ
dist/htmlhint.js	98.59% <100.00%> (+1.60%)	⬆️

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