feat: enable auto imports from utils dir

[pi0]

🔗 Linked issue

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 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)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

📝 Checklist

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

[pi0]

@antfu Do you have an idea why auto import works but #imports (dynamic gen by unimport.toExports in nitro.ts) and types (dynamic gen in build.ts by unimport.generateTypeDeclarations) do not include types for auto imports from dirs?

[codecov]

Codecov Report

Merging #866 (ead7a51) into main (a5586f8) will decrease coverage by 0.02%.
The diff coverage is 87.50%.

❗ Current head ead7a51 differs from pull request most recent head 7ba6c4a. Consider uploading reports for the commit 7ba6c4a to get more accurate results

@@            Coverage Diff             @@
##             main     #866      +/-   ##
==========================================
- Coverage   67.20%   67.19%   -0.02%     
==========================================
  Files          59       59              
  Lines        5797     5816      +19     
  Branches      617      621       +4     
==========================================
+ Hits         3896     3908      +12     
- Misses       1893     1899       +6     
- Partials        8        9       +1     

Impacted Files	Coverage Δ
src/build.ts	45.67% <80.00%> (-0.31%)	⬇️
src/options.ts	88.23% <92.30%> (+0.01%)	⬆️
src/nitro.ts	89.21% <100.00%> (+0.10%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[pi0]

Merging to try on edge/rc