Update proposal-lrhn.md

Make the non-accepted dot-shorthand proposal point to the one being implemented.

Author: lrhn

working/3616 - enum value shorthand/proposal-lrhn.md

@@ -1,5 +1,7 @@
 # Dart enum value shorthand
 
+(This is not the version being implemented. See the [simpler proposal](proposal-simple-lrhn.md).
+
 Pitch: Write `.foo` instead of `EnumName.foo` when possible.
 
 There are multiple levels of complexity possible for this functionality. This will start with the most basic version.