Fix: scroll_with_delta() for ScrollArea::vertical() and ScrollArea::horizontal()

[rustbasic]

Fix: scroll_with_delta() for ScrollArea::vertical() and ScrollArea::horizontal()

We need to do this in order for ScrollArea::vertical() and ScrollArea::horizontal() to work even where they are divided or nested.

Pull requests :

• Related Fix Ui::scroll_with_delta only scrolling if the ScrollArea is focused #4303
• Related Make scroll_to_* animations configurable #4305
• Related Fix: scroll_with_delta() for ScrollArea::vertical() and ScrollArea::horizontal() #4584

[lucasmerlin]

The current behavior matches the behavior documented in scroll_with_delta:

Scroll this many points in the given direction, in the parent [crate::ScrollArea].

I think the current behavior makes sense and if you want to scroll the parent ScrollArea it should be possible by calling scroll_with_delta outside of the child ScrollArea.

[rustbasic]

I think the current behavior makes sense and if you want to scroll the parent ScrollArea it should be possible by calling scroll_with_delta outside of the child ScrollArea.

It doesn't work when horizontal() and vertical() are separated.
Because the value is retrieved with take() and the value disappears,

ui.horizontal() {
  ui.vertical() {
    ScrollArea::vertical() {
      ui.label()
      ScrollArea::horizontal() {
      }
    }
  }
}

For example, if each line in TextEdit is numbered.