`accepted` callback should trigger when losing focus (incl. on window deactivation)

[Enyium]

As it stands - the accepted callback of a number of elements and widgets exclusively being triggered by pressing Enter - I find the callback quite useless. In my view, it should be a less often triggered alternative to edited, but one that will eventually always be triggered, like released on Slider (edited is parallel to Slider's changed).

[ogoffart]

Thanks for filing an issue. I agree that accepted is badly named. We can't change accepted, that would be a breaking change. What we can do is deprecate it and rename it to return-pressed. (We have infrastructure to do that in TextInput because it's builtin, but we don't have infrastructure to do that yet for component declared in the Slint language.)

Regardless, it does make sense to add a editing-finished callback to TextInput/LineEdit/TextEdit.