Merge pull request #109115 from mrbullwinkle/mrb_03_26_2020_asp_net_exceptions

Clarify code samples do not apply to .NET Core

Author: PRMerger12

articles/azure-monitor/app/asp-net-exceptions.md

@@ -24,6 +24,8 @@ Exceptions in your live web app are reported by [Application Insights](../../azu
   * [Web API 2.*](#web-api-2x)
   * [WCF](#wcf)
 
+  This article is specifically focused on .NET Framework apps from a code example perspective. Some of the methods that work for .NET Framework are obsolete in the .NET Core SDK. Refer to the [.NET Core SDK documentation](https://docs.microsoft.com/azure/azure-monitor/app/asp-net-core) if you have a .NET Core app.
+
 ## Diagnosing exceptions using Visual Studio
 Open the app solution in Visual Studio to help with debugging.