Make it more consistent to current implementation and other parts of …

…Any doc (antipairs).

doc/Type/Any.pod6

@@ -339,9 +339,14 @@ Interprets the invocant as a list, and returns the last index of that list.
 
 Defined as:
 
-    multi method pairup(Any:U: --> Seq)
+    multi method pairup(Any:U:)
     multi method pairup(Any:D:)
 
+Returns an
+empty L<Seq|/type/Seq> if the invocant is a type object
+
+    Range.pairup.say; # OUTPUT: «()␤»
+
 Interprets the invocant as a list, and constructs a list of
 L<pairs|/type/Pair> from it, in the same way that assignment to a
 L<Hash|/type/Hash> does.  That is, it takes two consecutive elements and