Markup block - Gen<None> - 16 - (0:0,0)
    Tag block - Gen<TagHelper> - 16 - (0:0,0) - p - PTagHelper
        StartTagAndEndTag - <p> ... </p>
        Tag block - Gen<TagHelper> - 4 - (3:0,3) - br - BRTagHelper
            StartTagOnly - <br>
        Markup span - Gen<Markup> - [Hello] - SpanEditHandler;Accepts:Any - (7:0,7) - Tokens:1
            HtmlTokenType.Text;[Hello];
