fix: don't clean root directory if set as outDir

[danielroe]

🔗 Linked issue

❓ 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

Let us draw a curtain of charity over how I discovered this issue.

I also considered warning + continue in this case but thought there would be valid use cases, such as wanting ./src/my-file.ts to output to ./some-file.js. However, if this is too edge-casey, I think we could add a warning as well.

📝 Checklist

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