Improve the code example and emphasize on the type parameter

Author: BartoszKlonowski

docs/csharp/misc/cs1031.md

@@ -13,6 +13,8 @@ ms.assetid: 14196659-aaac-4df2-a4ed-0bebb8097d59
 Type expected  
 
 A type has not been specified where expected, when [overloading an operator](../language-reference/operators/operator-overloading.md).
+<br/>Missing *type* in this case means that there's no *type* given for the return type of the overloaded operator.
+This error shouldn't be confused with missing [generic type parameter](../../csharp/programming-guide/generics/generic-type-parameters.md).
 
 ## Example
 
@@ -27,11 +29,14 @@ namespace x
 
     public class A
     {  
-        public static operator +(A aa)  // CS1031  
-                                        // try the following line instead  
-                                        // public static ii operator +(a aa)  
+        public static operator +(A a)    // CS1031 - Overloaded operator missing a type
         {
-            return new ii();
+            return new I();
+        }
+
+        public static I operator +(A a)  // Correct - type was specified
+        {
+            return new I();
         }
     }
 }