feat: add no-heading-inside-button rule

[yeonjuan]

ref #54

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.33%. Comparing base (b8e9f5b) to head (4491ea8).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #256      +/-   ##
==========================================
+ Coverage   98.32%   98.33%   +0.01%     
==========================================
  Files          62       63       +1     
  Lines        1729     1745      +16     
  Branches      469      472       +3     
==========================================
+ Hits         1700     1716      +16     
  Misses         29       29              

Flag	Coverage Δ
unittest	98.33% <100.00%> (+0.01%)	⬆️

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Files with missing lines	Coverage Δ
packages/eslint-plugin/lib/rules/index.js	100.00% <100.00%> (ø)
...slint-plugin/lib/rules/no-heading-inside-button.js	100.00% <100.00%> (ø)