Add cross reference comment to the rotation list

Author: spastorino

layouts/shortcodes/checkin-schedule.html

@@ -17,6 +17,8 @@
     var year = new Date(today.getFullYear(), 0, 1);
     var week = Math.floor(((today - year) / 86400000) / 7) + 1;
 
+    // This list is alphabetically sorted and matches the sorting we have on
+    // the working groups index page
     var wgs = [
         "Async/Await",
         "Diagnostics",