Update the material 3 design token docs (#12125)

This aligns the docs with the changes in
flutter/flutter#170000

---------

Co-authored-by: Shams Zakhour (ignore Sfshaza) <44418985+sfshaza2@users.noreply.github.com>
Co-authored-by: Brett Morgan <brettmorgan@google.com>

Author: 3 people

src/content/release/breaking-changes/index.md

@@ -41,12 +41,14 @@ They're sorted by release and listed in alphabetical order:
 * [`$FLUTTER_ROOT/version` replaced by `$FLUTTER_ROOT/bin/cache/flutter.version.json`][]
 * [`FontWeight` also controls the weight attribute of variable fonts][]
 * [Deprecate `TextField.canRequestFocus`][]
+* [Material 3 tokens update][]
 
 [Merged threads on Linux]: /release/breaking-changes/linux-merged-threads
 [Stop generating `AssetManifest.json`]: /release/breaking-changes/asset-manifest-dot-json
 [`$FLUTTER_ROOT/version` replaced by `$FLUTTER_ROOT/bin/cache/flutter.version.json`]: /release/breaking-changes/flutter-root-version-file
 [`FontWeight` also controls the weight attribute of variable fonts]: /release/breaking-changes/font-weight-variation
 [Deprecate `TextField.canRequestFocus`]: /release/breaking-changes/can-request-focus
+[Material 3 tokens update]: /release/breaking-changes/material-color-utilities
 
 <a id="released-in-flutter-338" aria-hidden="true"></a>
 ### Released in Flutter 3.38

src/content/release/breaking-changes/material-color-utilities.md

@@ -0,0 +1,43 @@
+---
+title: Material Color Utilities update in Flutter
+description: >-
+  The latest Material Color Utilities have been applied to the Flutter Material
+  library.
+---
+
+{% render "docs/breaking-changes.md" %}
+
+## Summary
+
+This release updates `package:material_color_utilities` from
+`v0.11.1` to `0.13.0`. This updated package includes algorithm changes that align
+with the [Material 3 tokens update](/release/breaking-changes/material-design-3-token-update).
+
+The algorithm changes affect the same properties:
+
+* `onPrimaryContainer`
+* `onSecondaryContainer`
+* `onTertiaryContainer`
+* `onErrorContainer`
+
+The changes will be reflected when generating a scheme using
+
+* `ColorScheme.fromSeed`
+* `ColorScheme.fromImageProvider`
+* `ThemeData(colorScheme:..)`
+
+## Migration guide
+
+In general, we believe the colors generated will be more legible and visually
+appealing, but if you want to maintain the previous colors when upgrading
+you will have to manually set those properties to their desired color after
+generating.
+
+## Timeline
+
+* Landed in version: `3.39.0-1.0.pre-250`
+* In stable release: TBD
+
+## References
+
+* Relevant commit: [Update material_color_utilities to v0.13.0](https://github.com/flutter/flutter/commit/153fd7fc603836d8d57032a9cb93118245dfba8c)