[Components][Config][Definition] Fix code sample

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.2+
| Fixed tickets | -

Well, I ain't sure about this one. Does `prototype()` need an `end()` node? Looking at the other examples it looks like so, but it would be great if someone could confirm.