Add an example of several cases with single implementation

Author: BartoszKlonowski

docs/csharp/language-reference/compiler-messages/cs0163.md

@@ -56,3 +56,26 @@ public class MyClass
     }  
 }
 ```
+
+Note that it is correct to have several `case`s for one implementation, like in the following snippet:
+
+```csharp
+public class MyClass
+{
+    public static void Main()
+    {
+        int i = 0;
+
+        switch(i)
+        {
+            case 1:
+            case 2:    // No CS0163
+                i++
+                break;
+
+            default:
+                break;
+        }
+    }
+}
+```