/// <summary>Called when the visitor visits a ArgumentSyntax node.</summary>
 public override SyntaxNode VisitArgument(ArgumentSyntax node)
 {
     if (node.ContainsAnnotations && node.HasAnnotation(Annotations.ThenArgument))
     {
         var r = base.VisitArgument(node) as ArgumentSyntax;
         return(r.WithLeadingTrivia(Tabs.BrTabs()));
     }
     return(base.VisitArgument(node));
 }