Support Visual Studio additions to the LSP

[StellaHuang95]

This was original opened by Rich. See https://github.com/microsoft/pyrx/issues/3466

Visual Studio has a number of additions to the LSP.

Unfortunately they're not documented yet. You can find them all by searching in this spot here: https://dev.azure.com/devdiv/DevDiv/_git/VSLanguageServerClient?path=/src/product/Protocol/LanguageServer.Protocol.Extensions&_a=contents&version=GBdevelop

Those are the classes created that add extra functionality to the LSP.

These are needed in order to get full intellisense support in VS using pylance.