fix example bug

Author: coke

doc/Language/js-nutshell.pod6

@@ -434,7 +434,7 @@ C<Supply.tap> is multithreaded; if this is undesirable, use C<Supply.act>
 instead:
 
 =begin code
-my $supply = IO::Socket::Async.listen('localhost', 8000)
+my $supply = IO::Socket::Async.listen('localhost', 8000);
 my $server = $supply.tap(-> $conn {
     $conn.Supply.tap(-> $data {
         say $data; # RESULT: ayy lmao