Markup block - Gen<None> - 19 - (0:0,0)
    Markup span - Gen<Markup> - [] - SpanEditHandler;Accepts:Any - (0:0,0) - Tokens:1
        SyntaxKind.Unknown;[];
    Directive block - Gen<None> - 19 - (0:0,0)
        Transition span - Gen<None> - [@] - SpanEditHandler;Accepts:None - (0:0,0) - Tokens:1
            SyntaxKind.Transition;[@];
        MetaCode span - Gen<None> - [addTagHelper] - SpanEditHandler;Accepts:None - (1:0,1) - Tokens:1
            SyntaxKind.Identifier;[addTagHelper];
        Markup span - Gen<None> - [ ] - SpanEditHandler;Accepts:None - (13:0,13) - Tokens:1
            SyntaxKind.Whitespace;[ ];
        Code span - Gen<AddTagHelper:{"Foo";Foo;;} [RZ1020(15:0,15 [3] )]> - ["Foo"] - SpanEditHandler;Accepts:AnyExceptNewline - (14:0,14) - Tokens:1
            SyntaxKind.StringLiteral;["Foo"];
    Markup span - Gen<Markup> - [] - SpanEditHandler;Accepts:Any - (19:0,19) - Tokens:1
        SyntaxKind.Unknown;[];
