Markup block - Gen<None> - 7 - (0:0,0)
    Tag block - Gen<None> - 6 - (0:0,0)
        Markup span - Gen<Markup> - [</foo>] - SpanEditHandler;Accepts:None - (0:0,0) - Tokens:4
            HtmlTokenType.OpenAngle;[<];
            HtmlTokenType.ForwardSlash;[/];
            HtmlTokenType.Text;[foo];
            HtmlTokenType.CloseAngle;[>];
    Markup span - Gen<Markup> - [ ] - SpanEditHandler;Accepts:None - (6:0,6) - Tokens:1
        HtmlTokenType.WhiteSpace;[ ];
