docs: add note about middleware execution order

[moshetanzer]

🔗 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

I think that the example doesn't give clarity to basic user regarding middleware execution, have added 0 in from of the numbers, and an info message for clarities sake.

Here is a basic repro

https://stackblitz.com/edit/github-ph5sly?file=server%2Froutes%2Findex.ts

📝 Checklist

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

[pi0]

Thanks.

[pi0]

Although having more than 10 middleware is strange...