Cleanup

[clragon]

This PR includes:

• applied formatting everywhere
• applied recommended flutter lints everywhere
• regenerated example
• applied more consistent code style

For future PRs to be considered:

• supportedPlatform seems outdated / incorrect. the latest flutter_keyboard_visibility supports all platforms except web.
• the code uses alot of unnecessary this.
• the hardcoded duration for dialogs might be resolvable by listening to the animation on the dialog route
• some public members are missing doc comments (enableInteractiveSelection, autofillHints)
• some widgets use static colors where it would be more appropriate to pull colors from the surrounding ThemeData

[clragon]

To resolve merge conflicts after this PR has been merged:

• open your branch
• git reset --soft <commit hash of the last commit before yours>
• stash all your changes
• git pull
• git reset --hard master
• unstash all your changes
• dart format .
• dart fix --apply
• double check formatting of your changed files
• commit and git push --force

note that these are destructive and powerful git commands.
please be careful with any unsaved work.
You can use "apply" instead of "pop" for git stashes to retain them in case something goes wrong.

[sjmcdowall]

@clragon -- I merged the code but after upgrading to flutter 3.15.3 (or whatever) 2 tests fail so I am not going to publish this yet ... can you submit fixes for the tests -- here is the output ...

…/master/flutter_typeahead  c6ff9b2  master ⍟4  flutter test  1 ↵  10013  16:53:01
00:03 +1: /Users/sjm/play/master/flutter_typeahead/test/cupertino_typeahead_test.dart: Cupertino TypeAhead widget tests Initial UI Test
══╡ EXCEPTION CAUGHT BY FLUTTER TEST FRAMEWORK ╞════════════════════════════════════════════════════
The following TestFailure was thrown running a test:
Expected: exactly 6 matching nodes in the widget tree
Actual: _WidgetTypeFinder:<5 widgets with type "CupertinoTypeAheadFormField" (ignoring
offstage widgets): CupertinoTypeAheadFormField(dependencies: [UnmanagedRestorationScope],
state: CupertinoTypeAheadFormFieldState#50797),
CupertinoTypeAheadFormField(dependencies: [UnmanagedRestorationScope], state:
CupertinoTypeAheadFormFieldState#b9d1c), CupertinoTypeAheadFormField(dependencies:
[UnmanagedRestorationScope], state: CupertinoTypeAheadFormFieldState#95302), ...>
Which: is not enough

When the exception was thrown, this was the stack:
#4 main.. (file:///Users/sjm/play/master/flutter_typeahead/test/cupertino_typeahead_test.dart:15:7)


(elided one frame from package:stack_trace)

This was caught by the test expectation on the following line:
file:///Users/sjm/play/master/flutter_typeahead/test/cupertino_typeahead_test.dart line 15
The test description was:
Initial UI Test
════════════════════════════════════════════════════════════════════════════════════════════════════
00:03 +1 -1: /Users/sjm/play/master/flutter_typeahead/test/cupertino_typeahead_test.dart: Cupertino TypeAhead widget tests Initial UI Test [E]
Test failed. See exception logs above.
The test description was: Initial UI Test

To run this test again: /Users/sjm/Development/tools/flutter/bin/cache/dart-sdk/bin/dart test /Users/sjm/play/master/flutter_typeahead/test/cupertino_typeahead_test.dart -p vm --plain-name 'Cupertino TypeAhead widget tests Initial UI Test'
00:03 +1 -1: /Users/sjm/play/master/flutter_typeahead/test/material_typeahead_test.dart: Material TypeAhead widget tests Initial UI Test
══╡ EXCEPTION CAUGHT BY FLUTTER TEST FRAMEWORK ╞════════════════════════════════════════════════════
The following TestFailure was thrown running a test:
Expected: exactly 6 matching nodes in the widget tree
Actual: _WidgetTypeFinder:<4 widgets with type "TypeAheadFormField" (ignoring offstage
widgets): TypeAheadFormField(dependencies: [UnmanagedRestorationScope], state:
_TypeAheadFormFieldState#a9836), TypeAheadFormField(dependencies:
[UnmanagedRestorationScope], state: _TypeAheadFormFieldState#264e9),
TypeAheadFormField(dependencies: [UnmanagedRestorationScope], state:
_TypeAheadFormFieldState#8219f), ...>
Which: is not enough

When the exception was thrown, this was the stack:
#4 main.. (file:///Users/sjm/play/master/flutter_typeahead/test/material_typeahead_test.dart:15:7)


(elided one frame from package:stack_trace)

This was caught by the test expectation on the following line:
file:///Users/sjm/play/master/flutter_typeahead/test/material_typeahead_test.dart line 15
The test description was:
Initial UI Test
════════════════════════════════════════════════════════════════════════════════════════════════════
00:03 +1 -2: /Users/sjm/play/master/flutter_typeahead/test/material_typeahead_test.dart: Material TypeAhead widget tests Initial UI Test [E]
Test failed. See exception logs above.
The test description was: Initial UI Test

To run this test again: /Users/sjm/Development/tools/flutter/bin/cache/dart-sdk/bin/dart test /Users/sjm/play/master/flutter_typeahead/test/material_typeahead_test.dart -p vm --plain-name 'Material TypeAhead widget tests Initial UI Test'
00:05 +20 -2: Some tests failed.

[clragon]

certainly, I will take a look.