* Add missing parameters to CheckboxListTile

* Update test message and api doc

* Reorder parameters

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Co-authored-by: Qun Cheng <quncheng@google.com>

* Add Material 3 `SwitchListTile` example and update existing examples

* Update examples with `useMaterial3: true` and update example descriptions.

* add a `ColorScheme` colour

* Add Material 3 `CheckboxListTile` example and update existing examples

* fix `list_tile.dart` doc issues

* Remove unnecessary comma

* dart fix --apply

* manual fixes

Move `ListTileTheme` and its tests into separate classes and  add `visualDensity` to the `ListTileTheme` (#100622)

This reverts commit 94ff5202.

This does a cleanup of the examples, removing all of the "section" markers and extra comments that we don't need anymore now that the samples are no longer in the source code. It also removes the --template arguments from the {@tool dartpad} and {@tool sample} directives, since those are no longer used. It converts two examples that I discovered were still embedded into linked examples in the examples folder.

I didn't delete the templates from the snippets config folder yet, because there are still embedded samples in the dart:ui package from the engine that use them. Once dart:ui no longer uses the templates, they can be removed.

I bumped the version of the snippets package to pick up a change that allows removal of the --template argument.

[CheckboxListTile, SwitchListTile, RadioListTile] Adds visualDensity, focusNode and enableFeedback (#89353)

This PR adds visualDensity, focusNode and enableFeedback to:

- CheckboxListTile
- SwitchListTile
- RadioListTile

This extracts the sample code out from the API doc comments, and places them in separate files on disk, allowing running of the examples locally, testing them, and building of slightly larger examples.

Update samples to use repo analysis options, Fix sample templates and a ton of analyzer issues (#77868)

This reverts commit 24bf6b81.

* migrate material to nullsafety

* address review comments

* address review comments

* fix build

* fix bug when tap ListTitle when tristate enable #63846

* fix bug when tap ListTitle when tristate enable #63846

* code style

* improve the unit test case

* bow to convention

* add language version 2.8 in packages/flutter

* enable non-nullable analyzer flag