Macro ui_component_layout_only 

macro_rules! ui_component_layout_only {
    ($ty:ty) => { ... };
}

Implement the UiBuilder patch + render glue for a component that supports layout refinements only.

The type must provide:

• fn refine_layout(self, LayoutRefinement) -> Self
• fn into_element(self, &mut ElementContext<'_, H>) -> AnyElement