fix: support more atrules parsing

[bartveneman]

closes #151
closes #79

[codecov-commenter]

Bundle Report

Changes will increase total bundle size by 3.17kB (2.16%) ⬆️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
@projectwallace/css-parser-esm	150.12kB	3.17kB (2.16%) ⬆️

Affected Assets, Files, and Routes:

view changes for bundle: @projectwallace/css-parser-esm

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
parse-*.js	3.02kB	25.9kB	13.19% ⚠️
parse.js	102 bytes	13.5kB	0.76%
arena.js	55 bytes	11.05kB	0.5%

Files in parse-*.js:

• ./src/parse-atrule-prelude.ts → Total Size: 25.08kB

Files in parse.js:

• ./src/parse.ts → Total Size: 12.62kB

Files in arena.js:

• ./src/arena.ts → Total Size: 10.1kB

[codecov-commenter]

Codecov Report

❌ Patch coverage is 97.70115% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 94.91%. Comparing base (c3af857) to head (b2323e3).

Files with missing lines	Patch %	Lines
src/parse-atrule-prelude.ts	97.61%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #153      +/-   ##
==========================================
+ Coverage   94.71%   94.91%   +0.19%     
==========================================
  Files          16       16              
  Lines        2726     2793      +67     
  Branches      713      736      +23     
==========================================
+ Hits         2582     2651      +69     
+ Misses        144      142       -2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.