[FEAT] Add ability to access doc.microsoft.com from context menu on right click of a namespace or a type

Add ability to access doc.microsoft.com from context menu on right click of a namespace or a type
and display in a readonly window like the in-memory creation of goto-definition

e.g. IHostingEnvironment
https://docs.microsoft.com/en-us/aspnet/core/api/Microsoft.AspNetCore.Hosting

Directory
https://docs.microsoft.com/en-us/dotnet/core/api/System.IO

and so on.