fix(dev): support extension patterns like `**/*.md`

[farnabaz]

🔗 Linked issue

resolves https://github.com/nuxt/content/issues/3410

❓ Type of change

• [ ] 📖 Documentation (updates to the documentation or readme)
• [x] 🐞 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.

[pkg-pr-new[bot]]

npm i https://pkg.pr.new/@nuxt/content@3414

commit: 6870b05

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