better description and example for Z

Author: gfldex

doc/Language/operators.pod6

@@ -2011,6 +2011,9 @@ Interleaves the lists passed to C<Z> like a zipper, stopping as soon as
 the first input list is exhausted:
 
     say (1, 2 Z <a b c> Z <+ ->).perl;  #=> ((1, "a", "+"), (2, "b", "-")).Seq
+    for <a b c> Z <1 2 3> -> $l, $r {
+        say "$l:$r"
+    }
 
 The C<Z> operator also exists as a meta operator, in which case the inner
 lists are replaced by the value from applying the meta'ed operator to the