Inconsistent new syntax highlighting for C#

[alexr00]

Originally from @gustavo-shigueo in microsoft/vscode#136442

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: 1.61.2
• OS Version: Windows 10 21H1

Some keywords have the wrong scope causing weird syntax highlighting

Steps to Reproduce:

1. Use more recent C# features such as target-typed new or the is not operation or the and/or keywords in a switch statement
2. Open the command pallete
3. Use the command "Developer: Inspect Editor Tokens and Scopes"

Sample code

using System;

namespace HelloWorld
{
	public class MyClass 
	{
		public MyClass()
		{
		}
	}

	class Program
	{
		static void Main(string[] args)
		{
			var stringArr = new[] { "", "" }; // new shows as keyword which is probably the expected behavior
			MyClass myClassInstance = new(); // new shows as a function call

			if (myClassInstance is not null) // is shows as keyword but not shows as a type annotation
			{
			}

			int x = 10;
			switch (x)
			{
				case > 1 and < 5 or 10: // both and and or show as variable names
					break;
				default:
					break;
			}
		}
	}
}

Screenshots:

[wise0704]

new is fixed in #258

pattern combinators are a separate issue (better described in #239)