Markup block - Gen<None> - 16 - (0:0,0)
    Markup span - Gen<Markup> - [<!DOCTYPE html>] - SpanEditHandler;Accepts:None - (0:0,0) - Tokens:6
        SyntaxKind.OpenAngle;[<];
        SyntaxKind.Bang;[!];
        SyntaxKind.Text;[DOCTYPE];
        SyntaxKind.Whitespace;[ ];
        SyntaxKind.Text;[html];
        SyntaxKind.CloseAngle;[>];
    Markup span - Gen<Markup> - [ ] - SpanEditHandler;Accepts:None - (15:0,15) - Tokens:1
        SyntaxKind.Whitespace;[ ];
