fix: type alignment...

include/jvalidate/detail/simple_adapter.h

@@ -173,7 +173,7 @@ public:
     // TODO(samjaffe): Needs type coercion
     switch (rhs_type) {
     case Type::Null:
-      return const_value().isNull();
+      return type() == Type::Null;
     case Type::Boolean:
       return rhs.as_boolean() == as_boolean();
     case Type::Integer: