simplify code, fix review

Author: DominicUllmann

src/Ninject.Web.AspNetCore/NinjectServiceProvider.cs

@@ -183,18 +183,13 @@ private static bool IsListType(Type type, out Type elementType)
 			if (type.IsGenericType)
 			{
 				Type genericTypeDefinition = type.GetGenericTypeDefinition();
-				if (genericTypeDefinition == typeof(List<>) || genericTypeDefinition == typeof(IList<>) ||
+				if (genericTypeDefinition == typeof(IEnumerable<>) ||
+				    genericTypeDefinition == typeof(List<>) || genericTypeDefinition == typeof(IList<>) ||
 				    genericTypeDefinition == typeof(ICollection<>))
 				{
 					elementType = type.GenericTypeArguments[0];
 					return true;
 				}
-
-				if (genericTypeDefinition == typeof(IEnumerable<>))
-				{
-					elementType = type.GenericTypeArguments[0];
-					return true;
-				}
 			}
 
 			elementType = null;