docs: refactor script setup lang="ts"

[shinGangan]

🔗 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)
• ✨ 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

Since <script setup lang="ts"> and <script lang="ts" setup> were mixed, we unified them to <script setup lang="ts">.

[vercel]

@shinGangan is attempting to deploy a commit to the Nuxt Team on Vercel.

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[shinGangan]

This PR only supports docs/ because it will affect the PRs currently being created.
After the current feature PR is merged, I will refactor the other directories (src/, client/, playground/) as well.

[shinGangan]

This PR isn't a feature development so it has a low review priority. 🙏

[harlan-zw]

Great love these small details!