message: Simplify `custom_widget` example
diff: @@ -37,14 +37,12 @@ mod circle {
  fn layout(
  &self,
  _renderer: &Renderer,
  - limits: &layout::Limits,
  + _limits: &layout::Limits,
  ) -> layout::Node {
  - let size = limits
  - .width(Length::Units(self.radius * 2))
  - .height(Length::Units(self.radius * 2))
  - .resolve(Size::ZERO);
  -
  - layout::Node::new(size)
  + layout::Node::new(Size::new(
  + f32::from(self.radius) * 2.0,
  + f32::from(self.radius) * 2.0,
  + ))
  }
  fn hash_layout(&self, state: &mut Hasher) {
  @@ -59,11 +57,9 @@ mod circle {
  layout: Layout<'_>,
  _cursor_position: Point,
  ) -> (Primitive, MouseCursor) {
  - let bounds = layout.bounds();
  -
  (
  Primitive::Quad {
  - bounds,
  + bounds: layout.bounds(),
  background: Background::Color(Color::BLACK),
  border_radius: self.radius,
  },
  