Suggested shortcut method similar to the Date methods in Datish.pm

If yyyy-dd-mm is a thing, then this at least adds consistency. ;)

src/core/DateTime.pm

@@ -257,6 +257,8 @@ my class DateTime does Dateish {
     method offset()            { $!timezone }
     method offset-in-minutes() { $!timezone / 60 }
     method offset-in-hours()   { $!timezone / 3600 }
+
+    method hh-mm-ss            { sprintf "%02d:%02d:%02d", $!hour,$!minute,$!second; }
 
     method later(:$earlier, *%unit) {
         my @pairs = %unit.pairs;