I would expect this to use symbol highlight not identifier highlight

Testing #2389

https://github.dev/dotnet/samples/blob/23c9784d57fc92436aa40043bf0a4b764308a923/csharp/NullableIntroduction/NullableIntroduction/SurveyQuestion.cs#L10-L17

![image](https://user-images.githubusercontent.com/6561887/135179817-2fe57bdb-a8e1-40e0-baa4-a45ed72b61b8.png)
