Acessibility: added AccessibilityAction and SupportedAccessibilityAction

[FloVanGH]

The adds only the enums / structs needed to implement accessibility actions. There is no functionality yet. This is the first step to implement #2872. The enum is a copy of the available accessibility actions provides by accesskit, before merging we need to check what is really needed for Slint and can be already implemented with the current feature set.

[tronical]

... before merging we need to check what is really needed for Slint and can be already implemented with the current feature set.

I share this sentiment. Perhaps we should just declare the ones we know are trivial to implement at this point and then add more later. That's basically Focus, Increment, Decrement, SetValue, SetTextSelection, SetValue, and perhaps ReplaceSelectedText. Maybe there are more?

[tronical]

I wonder what the expected behaviour here is. I wonder how to trigger this.

[FloVanGH]

... before merging we need to check what is really needed for Slint and can be already implemented with the current feature set.

I share this sentiment. Perhaps we should just declare the ones we know are trivial to implement at this point and then add more later. That's basically Focus, Increment, Decrement, SetValue, SetTextSelection, SetValue, and perhaps ReplaceSelectedText. Maybe there are more?

Agree. Make it easier to implement and the whole thing. And additional features can be extended later.

[ogoffart]

I don't think we should merge this as is in master, because there is no use for it without the code that uses it.

[FloVanGH]

I don't think we should merge this as is in master, because there is no use for it without the code that uses it.

Ok I can do a general wip/accessibility branch and we can merge it there. @ogoffart what do you think?

[tronical]

Good idea. If you call it feature/accessibility then it'll automatically CI tested (if you'd like that).

[FloVanGH]

Good idea. If you call it feature/accessibility then it'll automatically CI tested (if you'd like that).

done. I have also change this PR from master to the feature/accessibility branch.