WaitAsync extension methods on ValueTask and ValueTask{OfT}

[N1K0232]

As shown in the TaskExtensions file we have two extensions methods for the Task and Task{OfT} types, provided for the .NET Standard 2.0 environment.

Isn't it better to provide the same extensions methods for the ValueTask and ValueTask{OfT} types, just in case someone needs to use the ValueTask instead of Task?