Updated Design: Subflow Enhancements (markdown)

Design:-Subflow-Enhancements.md

@@ -1,3 +1,12 @@
+Parts of this design have now moved to the `node-red/designs` repository:
+
+ - https://github.com/node-red/designs/tree/master/designs/subflow-property-ui
+ - https://github.com/node-red/designs/tree/master/designs/exportable-subflow
+
+The parts of this design note that have already been merged for 0.20 have been left here.
+
+---
+
 ***This is a work in progress.***
 
 # SUBFLOW Customization