snafu with MAIN arg descriptions getting printed

ch3/ex3-4.raku

@@ -0,0 +1,9 @@
+# Take a decimal number and display it as a fraction.
+# Show the numerator and denominator
+use v6.d;
+
+sub MAIN (
+	Rat $num, #=A decimal number to turn into a fraction
+) {
+  say "Fractional value is {$num.numerator}/{$num.denominator}";
+}