Adds example to nodemap, refs #1720

Author: JJ

doc/Type/Any.pod6

@@ -269,6 +269,11 @@ C<nodemap> doesn't.
     say [[2,3], [[4,5],6,7], 7].map({.elems == 1 ?? $_ !! slip});
     # OUTPUT: «(7)␤»
 
+When applied to C<Associative>s, it will act on the values:
+
+    { what => "is", this => "thing" }.nodemap( *.flip ).say;
+    # OUTPUT: «{this => gniht, what => si}␤»
+
 =head2 method flat
 
 Defined as: