rework phrasing slightly.

(Avoids "it it" construct)

Author: coke

doc/Language/list.pod6

@@ -258,7 +258,7 @@ L<Exception|/type/Exception>.
     # OUTPUT: (sequence starting with «[1 11 121» ending with a 300 digit number)
 
 In the example above, C<@lazy-array> is an C<Array> which, through construction,
-is made C<lazy>. When calling C<is-lazy> on it it is returning an C<Iterator>,
+is made C<lazy>. Calling C<is-lazy> on it returns an C<Iterator>,
 which, since it originates in a lazy list, is itself lazy.
 
 A common use case for lazy C<Seq>s is the processing of infinite sequences of