Fix example to match new usage of dtkWidgetsLayoutWriter / Reader.
requested to merge 47-one-should-be-able-to-write-more-specifically-into-the-node-in-an-inheriting-class-of into develop
[A venir] Mise en place de quotas sur nos instances GitLab. Plus d'information sur : https://doc-si.inria.fr/pages/viewpage.action?pageId=129728565
[Coming soon] Quotas installation on our GitLab instances. More information: https://doc-si.inria.fr/pages/viewpage.action?pageId=129728565