Repository: flutter
Issue: ☂️ Document `dart:ui` where `public_member_api_docs` was not firing
Labels: engine,P2,c: tech-debt,team-engine,triaged-engine

In https://github.com/flutter/engine/pull/53539, I discovered that, perhaps due to a lack of a root pubspec, some Dart files were not being (fully?) linted:

```txt
Dart SDK version: 3.6.0-51.0.dev (dev) (Wed Jul 17 05:07:11 2024 -0700) on "linux_x64"

Analyzing ci...
No issues found!
Analyzing flutter_frontend_server...
No issues found!
Analyzing dart...
No issues found!
Analyzing gpu...
No issues found!
Analyzing ui...

   info - channel_buffers.dart:403:8 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - channel_buffers.dart:403:8 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - compositing.dart:249:11 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - compositing.dart:249:11 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - experiments/scene.dart:53:25 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - experiments/scene.dart:59:8 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - experiments/scene.dart:63:8 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - experiments/scene.dart:67:8 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - experiments/scene.dart:71:8 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - experiments/scene.dart:131:7 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - experiments/scene.dart:136:25 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - experiments/scene.dart:140:25 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - experiments/scene.dart:147:12 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - experiments/scene.dart:151:26 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - experiments/scene.dart:155:18 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - experiments/scene.dart:189:8 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - key.dart:19:14 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - key.dart:19:14 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - key.dart:49:14 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - key.dart:49:14 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - painting.dart:2601:11 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - painting.dart:2601:11 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - platform_dispatcher.dart:2198:9 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - platform_dispatcher.dart:2198:9 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - semantics.dart:287:36 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - semantics.dart:287:36 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - semantics.dart:289:27 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - semantics.dart:289:27 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - semantics.dart:641:34 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - semantics.dart:641:34 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - semantics.dart:643:25 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
   info - semantics.dart:643:25 - Missing documentation for a public member. Try adding documentation for the member. - public_member_api_docs
```

These obviously can't be fixed automatically, and it would be good to stem the bleeding, so I'll add `// ignore: ...`'s and link here.