This reverts commit bf8e1270.

This fixes #71222

* Implement operator = and hashcode for CupertinoThemeData and CupertinoTextThemeData which CupertinoThemeData depends on.
* Add basic tests for CupertinoThemeData equality and hashcode.

I also manually tested the case mentioned in #71222, e.g. equality of ThemeData(cupertinoOverrideTheme: someTheme)
Co-authored-by: Jacob Simionato <jsimionato@google.com>

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.

Switch document generation to use the snippets package instead of the snippets code in the Flutter repo. In the process, some bugs in sample code analysis have been fixed, and I've fixed some more errors in the samples.

This will allow the snippets package to be developed separately from the Flutter repo, and reduce the code in the Flutter repo.

The snippets code is deleted in this PR.

I also converted some comments in the snippet templates to be regular comments instead of doc comments, because having a doc comment block before the imports causes the Dart import sorter to lose the comment. They should have been regular comments in the first place.

The snippets package resides in the assets-for-api-docs repo.

The sample analysis has also been converted to be run in parallel, and I've bumped the Dartdoc version to 1.0.2.

* Add requestPrivacy parameter to TextField

* remove logs

* No need to pass _Editable requestPrivacy for now

* Forgot from last commit

* Add requestPrivacy flag to text form field

* Update docs

* Add requestPrivacy to CupertinoTextField

* Add test to verify requestPrivacy flag is sent to engine properly

* update docs

* fix tests

* rename requestPrivacy to enableIMEPersonalizedLearning

* Update text_input.dart

* default to true

* Have diagnostic properties default to true for enableIMEPersonalizedLearning

This reverts commit d056500b.

This reverts commit 31de052e.

This reverts commit e2490f29.

Clarify that minLines/maxLines affect the height of the field and not the number of lines that can be entered.

[TextSelectionControls] move the tap gesture callback into _TextSelectionHandlePainter, remove `_TransparentTapGestureRecognizer`. (#83639)