public override JsonSyntax VisitWhitespaceSyntax(JsonWhitespaceSyntax node, _void arg) => node;
public virtual TResult VisitWhitespaceSyntax(JsonWhitespaceSyntax node, T arg) => DefaultVisit(node, arg);
public override IGreenJsonSymbol VisitWhitespaceSyntax(JsonWhitespaceSyntax node, _void arg) => node.Green;