Adds duckmap example, closes #1720

Author: JJ

doc/Type/Any.pod6

@@ -215,12 +215,16 @@ Defined as:
 
 C<duckmap> will apply C<&block> on each element that behaves in such a way that
 C<&block> can be applied. If it fails, it will descend recursively if possible,
-or otherwise return the item without any transformation.
+or otherwise return the item without any transformation. It will act on
+values if the object is C<Associative>.
 
-    <a b c d e f g>.duckmap(-> $_ where <c d e>.any { .uc }).say;
-    # OUTPUT: «(a b C D E f g)␤»
-    (('d', 'e'), 'f').duckmap(-> $_ where <e f>.any { .uc }).say;
-    # OUTPUT: «((d E) F)␤»
+=for code
+<a b c d e f g>.duckmap(-> $_ where <c d e>.any { .uc }).say;
+# OUTPUT: «(a b C D E f g)␤»
+(('d', 'e'), 'f').duckmap(-> $_ where <e f>.any { .uc }).say;
+# OUTPUT: «((d E) F)␤»
+{ first => ('d', 'e'), second => 'f'}.duckmap(-> $_ where <e f>.any { .uc }).say;
+# OUTPUT: «{first => (d E), second => F}␤»
 
 In the first case, it is applied to C<c>, C<d> and C<e> which are the ones that
 meet the conditions for the block (C<{ .uc }>) to be applied; the rest are