DOC(dev): update 21_hugo-theme_update-git-submodule.md

Documentation/doc_for-developer/21_hugo-theme_update-git-submodule.md

@@ -19,10 +19,11 @@ git commit -m "CHORE: update submodule ref"
 > We strongly recommend to follow the following examples
 > for the commit message and the merge request :
 >
-> - [commit example](https://gitlab.adullact.net/adullact/faq.adullact.org/-/commit/b535a0be82fa4557257eafb5890afc7ebcc93eea)
+> - [commit example](https://gitlab.adullact.net/adullact/faq.adullact.org/-/commit/2623374c462c403447d564e6738050df417789dc)
 >   - Add a link to old commit used for theme sub-module before update
 >   - Add a link to new commit used for theme sub-module after update
-> - [Merge request example](https://gitlab.adullact.net/adullact/faq.adullact.org/-/merge_requests/64)
+>   - Add BREAKING CHANGE footer with a message for developers:<br> "BREAKING CHANGE: update Git submodule on your local repository"
+> - [Merge request example](https://gitlab.adullact.net/adullact/faq.adullact.org/-/merge_requests/146)
 >   - Add a link to old commit used for theme sub-module before update
 >   - Add a link to new commit used for theme sub-module after update
 >   - Add a message for developers : "To do : after the merge of the MR ..."