MarkupBlock - [0..16)::16 - [<foo>@@bar</foo>]
    MarkupTagBlock - [0..5)::5 - [<foo>]
        MarkupTextLiteral - [0..5)::5 - [<foo>] - Gen<Markup> - SpanEditHandler;Accepts:None
            OpenAngle;[<];
            Text;[foo];
            CloseAngle;[>];
    MarkupEphemeralTextLiteral - [5..6)::1 - [@] - Gen<None> - SpanEditHandler;Accepts:Any
        Transition;[@];
    MarkupTextLiteral - [6..10)::4 - [@bar] - Gen<Markup> - SpanEditHandler;Accepts:Any
        Transition;[@];
        Text;[bar];
    MarkupTagBlock - [10..16)::6 - [</foo>]
        MarkupTextLiteral - [10..16)::6 - [</foo>] - Gen<Markup> - SpanEditHandler;Accepts:None
            OpenAngle;[<];
            ForwardSlash;[/];
            Text;[foo];
            CloseAngle;[>];
