Do not thread note

Since `say` shall not[^1] thread and `note` is just a `say`
that outputs to STDERR instead of STDOUT, it shan't thread
either for the same reasons (Junction.gist is a string, and
so `say` should just output that string instead of special-casing
anything)

[1] https://irclog.perlgeek.de/perl6-dev/2018-02-27#i_15864766

src/core/io_operators.pm6

@@ -46,9 +46,6 @@ multi sub note() {
     my $err := $*ERR;
     $err.print(nqp::concat("Noted",$err.nl-out));
 }
-multi sub note(Junction:D \j) {
-    j.THREAD(&note)
-}
 multi sub note(**@args is raw) {
     my $err := $*ERR;
     my str $str;