[PAGE ISSUE]: 'Basic Flutter layout concepts'

[domesticmouse]

Page URL

https://docs.flutter.dev/codelabs/layout-basics/

Page source

https://github.com/flutter/website/tree/main/src/codelabs/layout-basics.md

Describe the problem

From @selhuberb's bug report: dart-lang/dart-pad#2231:

I started having a look into Flutter development and I'm therefore having a look into your provided trainings.
At the following training nearly every Dart editor is showing issues:
https://docs.flutter.dev/codelabs/layout-basics

Expected fix

The code samples shouldn't trigger lint warnings

Additional context

No response