Added obsolete alias for old typo'd value.

src/Avalonia.Input/Cursors.cs

@@ -40,6 +40,9 @@ namespace Avalonia.Input
         DragLink,
         None,
 
+        [Obsolete("Use BottomSide")]
+        BottomSize = BottomSide
+
         // Not available in GTK directly, see http://www.pixelbeat.org/programming/x_cursors/ 
         // We might enable them later, preferably, by loading pixmax direclty from theme with fallback image
         // SizeNorthWestSouthEast,