Document the @xs parameter of challenge 131 task 1

Because it needs to be sorted, but the error given otherwise is useless.

1 files changed, 4 insertions, 1 deletions

diff --git a/challenge-131/ben-davies/raku/ch-1.raku b/challenge-131/ben-davies/raku/ch-1.raku
index 51446f4d4c..192c2a009a 100644
--- a/challenge-131/ben-davies/raku/ch-1.raku
+++ b/challenge-131/ben-davies/raku/ch-1.raku
@@ -1,5 +1,8 @@
 use v6;
-unit sub MAIN(**@xs where .all ~~ Int:D & &(* > 0) && .&[~~](.sort)) {
+unit sub MAIN(
+    #|[ A sorted list of positive integers. ]
+    **@xs where .all ~~ Int:D & &(* > 0) && .&[~~](.sort)
+) {
     say gather @xs .= skip: take [@xs[0...&end-of-seq]] while @xs;
     sub end-of-seq(Int:D $i) { $i >= @xs - 1 or @xs[$i + 1] != @xs[$i] + 1 }
 }