Fix diacritics input in BTF2 on macOS via long-press

[m-sasha]

Fix diacritics input in BTF2 on macOS via long-press.

Note that the fix itself is to call textInputService.updateState whenever the text changes. The changes in DesktopPlatformInput.desktop.kt are just a minor refactoring.

Testing

Tested manually by long-pressing 'c' on:

val state = rememberTextFieldState()
TextField(state, modifier = Modifier.width(200.dp))

Unfortunately the implementation is not robust enough to be tested automatically. It depends on a call to InputMethodRequests.getSelectedText to activate the behavior, which is not possible to do in a test. We may want to improve this implementation in the future, by imitating what Swing does in JTextComponent.replaceInputMethodText.

This should be tested by QA

Release Notes

Fixes - Desktop

Fixed input of diacritics via long-press on macOS in TextField(TextFieldState) (aka BasicTextField2).

[igordmn]

Did you check that input method languages still work (Chinese, etc)?

[igordmn]

I checked Chinese - works in BTF1/BTF2 on Windows

[m-sasha]

Did you check that input method languages still work (Chinese, etc)?

Chinese works.