Clarify pick

Note that only in method form can count be omitted to
produce a single item instead of a Seq

Author: zoffixznet

doc/Type/List.pod6

@@ -517,8 +517,8 @@ and without repetition from the invocant. If C<*> is passed as C<$count>,
 or C<$count> is greater than or equal to the size of the list, then all
 elements from the invocant list are returned in a random sequence.
 
-If C<$count> is omitted: Returns a single random item from the list, or
-Nil if the list is empty
+In I<method> form, if C<$count> is omitted: Returns a single random item from
+the list, or Nil if the list is empty
 
 Examples: