C# Arrow functions with string breaking color themes

[mnsr]

VS Code: 1.4.0

This issue is similar to this one for TS: #3919

But in this case, it's happening in C# after using an arrow function AND the new string format syntax:

protected string Name(string name) => $"My Name is {name}";

if you remove the curly braces from the string, it's fine:

protected string Name(string name) => $"My Name is name";

[alexdima]

Moved to dotnet/vscode-csharp#679