message: Implement event capturing for `Slider`
diff: @@ -234,6 +234,8 @@ where
  if layout.bounds().contains(cursor_position) {
  change();
  self.state.is_dragging = true;
  +
  + return event::Status::Captured;
  }
  }
  mouse::Event::ButtonReleased(mouse::Button::Left) => {
  @@ -242,11 +244,15 @@ where
  messages.push(on_release);
  }
  self.state.is_dragging = false;
  +
  + return event::Status::Captured;
  }
  }
  mouse::Event::CursorMoved { .. } => {
  if self.state.is_dragging {
  change();
  +
  + return event::Status::Captured;
  }
  }
  _ => {}
  