Added support for scoped css attribute

[egil]

Pull request description

closes #176

PR meta checklist

• Pull request is targeting at DEV branch.
• Pull request is linked to all related issues, if any.
• I have read the CONTRIBUTING.md document.

Content checklist

• My code follows the code style of this project and AspNetCore coding guidelines.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
• I have updated the appropriate sub section in the CHANGELOG.md.
• I have added, updated or removed tests to according to my changes.
  • All tests passed.

[codecov]

Codecov Report

Merging #195 into dev will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##              dev     #195   +/-   ##
=======================================
  Coverage   77.78%   77.79%           
=======================================
  Files          99       99           
  Lines        2863     2864    +1     
  Branches      352      353    +1     
=======================================
+ Hits         2227     2228    +1     
  Misses        519      519           
  Partials      117      117           

Impacted Files	Coverage Δ
src/bunit.web/Rendering/Internal/Htmlizer.cs	83.54% <100.00%> (+0.10%)	⬆️

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[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities (and 0 Security Hotspots to review)
0 Code Smells

No Coverage information
0.0% Duplication