Adds a note mentioning that this is still a release preview.

* fixes wheel gradient and adds test

New locale resolution algorithm to use full preferred locale list, include scriptCode in Locale. (#23583)

* Introduce a rounded InputBorder with no paint

* Update documentation for API

* Change name of Widget to NoStrokeInputBorder and updated documentation

* [FilledInputBorder] PR feedback.

* [FilledInputBorder] typo correction.

* [FilledInputBorder] Removing news.

* [FilledInputBorder] PR feedback.

* [FilledInputBorder] Removing use of borderSide.

* [FilledInputBorder] Adding tests for hashcode.

* [FilledInputBorder] Comments.

* [TextFields] Input decoration feature parity.

* [TextFields] Making floating of placeholder optional.

* [TextFields] Cleanup

* [TextFields] Removing unused isAnimated.

* [TextFields] Cleanup.

* [TextFields] Correcting border.

* [TextFields] Correcting comment.

* [TextFields] Comment.

* [TextFields] Corrections for tests.

* [TextFields] Cleanup.

* [TextFields] Cleanup.

* [TextFields] Tests.

* [TextFields] Cleanup.

* [TextFields] Cleanup.

* [TextFields] Formatting.

* [TextFields] PR feedback.

* [TextFields] PR feedback.

* [TextFields] PR feedback.

* Adds user account header arrow animation and test

* clarify widgetsapp docs

* Rename shadowed param, update doc

* pageContentBuilder

This converts existing ## Sample code samples to {@tool sample}...{@end-tool} form.

Also:
1. Fixed a minor bug in analyze-sample-code.dart
2. Made the snippet tool only insert descriptions if the description is non-empty.
3. Moved the Card diagram to before the code sample.

We have templates now.

* adds fix for rounding error

* update assert add test

* update docs

Should fix #22226.

Code introduced in #20890 caused a regression that broke color flooding animations in a BottomNavigationBar that has BottomNavigationBarType.shifting.

The original issue (#19653) dealt with background color changes not occurring until another tab was selected. The result is that the background color instantly changes whenever the state changes and when the widget changes, instead of allowing a new widget to animate the background color change.

* early return for initialRoute + test

This reverts commit 71e9bd6f.

This rewrites the sample code analysis script to be a little less of a hack (but still not pretty), and to handle snippets as well.

It also changes the semantics of how sample code is handled: the namespace for the sample code is now limited to the file that it appears in, so some additional "Examples can assume:" blocks were added. The upside of this is that there will be far fewer name collisions.

I fixed the output too: no longer will you get 4000 lines of numbered output with the error at the top and have to grep for the actual problem. It gives the filename and line number of the original location of the code (in the comment in the tree), and prints out the source code on the line that caused the problem along with the error.

For snippets, it prints out the location of the start of the snippet and the source code line that causes the problem. It can't print out the original line, because snippets get formatted when they are written, so the line might not be in the same place.

`RenderEditable.paint` assumes that if the length of the text fits within the
visible region, then the text will be rendered at the start of the region and be
completely visible. This is not always true, since the text may still be
rendered at an offset if an animation is ongoing when the text begins to fit.

This fixes #22288 and #14121

* Makes FlexibleSpaceSettingsPublic and adds a test

This reverts commit 76a1abd4.

* Adds functionality for progress indicator height to be controlled by the parent.

See https://github.com/flutter/flutter/issues/17910

So we're sure that:
1. We won't break the API by not allowing to mutate fields
2. We won't forget to markNeedsAddToScene after mutation

This reverts commit 949cfcf1.