.NET 6 docs for ClaimsPrincipal refer to ClaimsAuthorizationManager which does not exist in .NET 6 or .NET Core

.NET 6 docs for `ClaimsPrincipal` (https://docs.microsoft.com/en-us/dotnet/api/system.security.claims.claimsprincipal?view=net-6.0) read:
"You can front your resources with a claims processing pipeline, which can deal with authentication requests and authorization policy even before execution reaches your code. For example, you can configure a web-based application or service with a custom claims authentication manager, an instance of a class that derives from the ClaimsAuthenticationManager class."

This is incorrect - `ClaimsAuthenticationManager` is only available in WIF and .NET Framework 4.5 to 4.8.