Add SnapToNearestEdge class

[fujidaiti]

The SnapToNearestEdge is a subclass of SnappingSheetBehavior , which will snap to the closest edge within the sheet's draggable range. This feature is handy as it serves as a simplified and performance-optimized version of a SnapToNearest which only consists of two snap positions, namely minExtent and maxExtent.

// SnapToNearestEdge is functionally identical to this:
SnapToNearest(
  snapTo: [ minExtent, maxExtent ],
);