Directive block - Gen<None> - 17 - (0:0,0)
    Transition span - Gen<None> - [@] - SpanEditHandler;Accepts:None - (0:0,0) - Tokens:1
        CSharpTokenType.Transition;[@];
    MetaCode span - Gen<None> - [addTagHelper] - SpanEditHandler;Accepts:None - (1:0,1) - Tokens:1
        CSharpTokenType.Identifier;[addTagHelper];
    Markup span - Gen<None> - [ ] - SpanEditHandler;Accepts:None - (13:0,13) - Tokens:1
        CSharpTokenType.WhiteSpace;[ ];
    Code span - Gen<AddTagHelper:{Foo;Foo;;} [RZ1036(14:0,14 [3] )]> - [Foo] - SpanEditHandler;Accepts:AnyExceptNewline - (14:0,14) - Tokens:1
        CSharpTokenType.Identifier;[Foo];
