fix(prerender): only match href attribute after whitespace

[danielroe]

🔗 Linked issue

resolves #1527

❓ Type of change

• 📖 Documentation (updates to the documentation, readme, or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

This restricts href regexp to match only href and not x-link:href (for example).

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[codecov]

Codecov Report

Merging #1530 (4a1bfbf) into main (451d314) will not change coverage.
Report is 5 commits behind head on main.
The diff coverage is 100.00%.

❗ Current head 4a1bfbf differs from pull request most recent head 5b3f217. Consider uploading reports for the commit 5b3f217 to get more accurate results

@@           Coverage Diff           @@
##             main    #1530   +/-   ##
=======================================
  Coverage   76.25%   76.25%           
=======================================
  Files          73       73           
  Lines        7478     7478           
  Branches      734      734           
=======================================
  Hits         5702     5702           
  Misses       1775     1775           
  Partials        1        1           

Files Changed	Coverage Δ
src/prerender.ts	87.07% <100.00%> (ø)

[pi0]

Thanks! (added fixture too)