Fix bill creation grammar

psGrammar/challenge/nea/removeAddBillItem.jsgf

 #JSGF V1.0;
 grammar removeAddBillItem;
 
-public <removeAddBillItem> = ([the] <drink> [is missing] [(on|in) the (bill|list)]|[the] <drink> [(is|was) wrong]|remove [the] <drink> [from the (bill|list)| add [the] <drink> to the (bill|list));
+public <removeAddBillItem> = <add>|<remove>;
 
+<add> = <addA> | <addB>;
+<addA> = [the] <drink> [<verb> missing] [<preposition> the <bill>];
+<addB> = [please] add [the] <drink> [to the <bill>];
+<remove> = <removeA> | <removeB>;
+<removeA> = [the] <drink> [<verb> wrong];
+<removeB> = [please] remove [the] <drink> [from the <bill>];
+<bill> = (bill|list);
+<verb> = (is|was);
+<preposition> = (on|in);
 <drink> = (coke|malz|lemonade|water|ice tea|coffee);