message: fix: arc example
diff: @@ -80,7 +80,7 @@ impl<Message> canvas::Program<Message> for Arc {
  _cursor: Cursor,
  ) -> Vec<Geometry> {
  let geometry = self.cache.draw(bounds.size(), |frame| {
  - let palette = theme.palette();
  + let palette = theme.clone().palette();
  let center = frame.center();
  let radius = frame.width().min(frame.height()) / 5.0;
  