Fixed make_class example. (#1258)

The example only makes sense if `C2` is the class examined, as that's the one we dynamically created.

docs/examples.md

@@ -689,7 +689,7 @@ Sometimes you may want to create a class programmatically.
 >>> C2 = make_class("C2", {"x": field(type=int), "y": field()})
 >>> fields(C1) == fields(C2)
 True
->>> fields(C1).x.type
+>>> fields(C2).x.type
 <class 'int'>
 ```