added open generic support for decorator func

Author: Kamil Zakiev

src/Scrutor/ServiceCollectionExtensions.Decoration.cs

@@ -258,6 +258,16 @@ private static bool IsSameGenericType(Type t1, Type t2)
             return t1.IsGenericType && t2.IsGenericType && t1.GetGenericTypeDefinition() == t2.GetGenericTypeDefinition();
         }
 
+        private static IServiceCollection DecorateOpenGeneric(this IServiceCollection services, Type serviceType, Func<object, IServiceProvider, object> decorator)
+        {
+            if (services.TryDecorateOpenGeneric(serviceType, decorator))
+            {
+                return services;
+            }
+
+            throw new MissingTypeRegistrationException(serviceType);
+        }
+
         private static bool TryDecorateOpenGeneric(this IServiceCollection services, Type serviceType, Type decoratorType)
         {
             bool TryDecorate(Type[] typeArguments)