Remove warning about parser signature being wrong

src/parsers/nothing.c

 #include "parser_internal.h"
 
-static HParseResult* parse_nothing() {
+static HParseResult* parse_nothing(void* x,HParseState* y) {
+  (void)(x);
+  (void)(y);
   // not a mistake, this parser always fails
   return NULL;
 }