message: Complete `Scrollable::hash_layout`
diff: @@ -5,6 +5,8 @@ use crate::{
  pub use iced_core::scrollable::State;
  +use std::hash::Hash;
  +
  /// A scrollable [`Column`].
  ///
  /// [`Column`]: ../column/struct.Column.html
  @@ -69,15 +71,15 @@ where
  + self.state.offset(bounds, content_bounds) as f32,
  )
  } else {
  + // TODO: Make `cursor_position` an `Option<Point>` so we can encode
  + // cursor unavailability.
  + // This will probably happen naturally once we add multi-window
  + // support.
  Point::new(cursor_position.x, -1.0)
  };
  - self.content.on_event(
  - event,
  - layout.children().next().unwrap(),
  - cursor_position,
  - messages,
  - )
  + self.content
  + .on_event(event, content, cursor_position, messages)
  }
  fn draw(
  @@ -99,6 +101,12 @@ where
  }
  fn hash_layout(&self, state: &mut Hasher) {
  + std::any::TypeId::of::<Scrollable<'static, (), ()>>().hash(state);
  +
  + self.height.hash(state);
  + self.max_height.hash(state);
  + self.align_self.hash(state);
  +
  self.content.hash_layout(state)
  }
  }
  