C#: Add ASP.NET Core MapGet routing end point example.

Author: michaelnebel

csharp/ql/test/library-tests/dataflow/flowsources/aspremote/AspRemoteFlowSource.cs

@@ -1,3 +1,4 @@
+using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Mvc;
 
 namespace Testing
@@ -20,4 +21,19 @@ public object MyAction(ViewModel viewModel)
             throw null;
         }
     }
+
+    public class AspRoutingEndpoints
+    {
+
+        public void M1(string[] args)
+        {
+            var builder = WebApplication.CreateBuilder(args);
+            var app = builder.Build();
+
+            // The delegate parameters are considered flow sources.
+            app.MapGet("/api/redirect/{newUrl}", (string newUrl) => { });
+
+            app.Run();
+        }
+    }
 }