Sort all child nodes based on their Y positions. The child node must inherit from [CanvasItem] for it to be sorted. Nodes that have a higher Y position will be drawn later, so they will appear on top of nodes that have a lower Y position.
Nesting of YSort nodes is possible. Children YSort nodes will be sorted in the same space as the parent YSort, allowing to better organize a scene or divide it in multiple ones, yet keep the unique sorting.
