* Add support for image insertion on Android
* Fix checks
* Use proper Dart syntax on snippet
* Specify type annotation on list
* Fix nits, add some asserts, and improve example code
* Add missing import
* Fix nullsafety error
* Fix nullsafety error
* Remove reference to contentCommitMimeTypes in docs
* Fix nits
* Fix warnings and import
* Add test for content commit in editable_text_test.dart
* Check that URIs are equal in test
* Fix nits and rename functions / classes to be more self-explanatory
* Fix failing debugFillProperties tests
* Add empty implementation to `insertContent` in TextInputClient
* Tweak documentation slightly
* Improve docs for contentInsertionMimeTypes and fix assert
* Rework contentInsertionMimeType asserts
* Add test for onContentInserted example
* Switch implementation to a configuration class for more granularity in setting mime types
* Fix nits
* Improve docs and fix doc tests
* Fix more nits (LongCatIsLooong)
* Fix failing tests
* Make parameters (guaranteed by platform to be non-nullable) non-nullable
* Fix analysis issues
