Remove IntelliCode section

The link was dead. I don't think this model is being created anymore.

Author: drewnoakes

CONTRIBUTING.md

@@ -17,11 +17,5 @@ For additional information, see the following:
 - [Architecture](docs/repo/architecture.md)
 - [Rules of the Project System](docs/repo/rules-of-the-project-system.md)
 - [Visual Studio Threading Guidelines](https://github.com/Microsoft/vs-threading/blob/master/doc/index.md)
-- [Common Project System (CPS) Documention](https://github.com/microsoft/vsprojectsystem)
+- [Common Project System (CPS) Documention](https://github.com/microsoft/VSProjectSystem)
 - [Code of Conduct](https://github.com/dotnet/home/blob/master/guidance/be-nice.md)
-
-# IntelliCode
-
-To provide better IntelliSense results when working with this project in Visual Studio 2019 or later, you can [add our IntelliCode model](https://docs.microsoft.com/en-us/visualstudio/intellicode/share-models#add-a-custom-model) to your installation.
-
-https://prod.intellicode.vsengsaas.visualstudio.com/get?m=A17F43B28B8B4488B7A89D27F33E1BB6