feat(config): provide defineContentConfig utility

[ineshbose]

🔗 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

This is NOT a breaking change.

Devs can still use export const collection (as c12 will fallback non-default export). However, in consistency with other .config files that tend to use default export and providing type-safety, having defineContentConfig would be nice.

📝 Checklist

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

[pkg-pr-new]

npm i https://pkg.pr.new/@nuxt/content@2891

commit: 6f8e257

[ineshbose]

Note: I've just added ability to use defineContentConfig without needing to import, but it may be a bit experimental. Let me know if you want to exclude from this PR for now.

[farnabaz]

LGTM 👍

Thanks