Hi Rabih,
agree with the conclusion that documentation is wrong. That page is clearly for traditional, so that comment was added at the top by accident in august of 2021, I think. You can help Outsystems by going to this documentation page and report your findings.
The documentation for Reactive is here.
So in Reactive, they have taken away some of the options for customizing that were there in reactive, apparently. If you really need this semi circle option, you could look into the js library they refer to on the Traditional page, and make your own widget, maybe.
Dorine