remove comment as our parser cant handle this

psGrammar/demos/demoDynamic.jsgf

@@ -19,7 +19,6 @@ public <command> = [<robot>] ( <introduce> | <save> | <wave> | <goTo> | <followM
 <describe> = (tell me what you see);
 <difference> = (spot the difference);
 
-// unused
 <handover> = handover;
 <ordering> = (start taking orders) | (take my order);
 <learn> = (learn a person);