Of the original 4 examples, the first 3 mostly covered the same API features and occupied quite a bit of real-estate at the top of https://api.flutter.dev/flutter/material/FloatingActionButton-class.html.  Additionally the illustrations and the code samples didn't match in some cases.

Replaced examples 0,1,2 with one example that changes attributes of the FAB when it's pushed. 

Fixes https://github.com/flutter/flutter/issues/128048

Remove 1745 decorative breaks

Update Material tokens to 0.162

* Update to v0.158 of the token database.

* Update checkbox template

* Fix DatePickerTheme test

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

* dart fix --apply

* manual fixes

* Updated to tokens v0.150.

* Updated with a reverted list_tile.dart.

Refactor gen_defaults to support multiple generated code blocks in the same file independently. (#107278)

* Improve `useMaterial3` documentation

* reverse styles and components

* tweak language around support

* Update theme_data.dart

* remove trailing space

* Update packages/flutter/lib/src/material/theme_data.dart
Co-authored-by: Darren Austin <darren@darrenaustin.org>

* add missing spec links

* remove spec links from useMaterial3

* move defaults section up, rejig things

* spaces no longer trailing

* spaces no longer trailing (2)
Co-authored-by: Darren Austin <darren@darrenaustin.org>

Also added the Card tokens to the exported list.

Added the navigation_rail.json as well.

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.

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.