Fix alignment of items in nuxeo-directory-suggestion with the attribute multiple="true"

Steps to reproduce:

1. copy the attached jar to nxserver/plugins
2. start Nuxeo
3. Log in
4. navigate to the search "Ope" (the one with a "user" icon)
5. Click on the Typology drop down and scroll till the end of the list
6. Observe that the "Modification" item is at the same level (same indentation) than the previous item but "Modification is a child of "Documents PCA", not "Directives techniques complémentaires"

Expected behavior: "Modification" should be aligned with "Directives techniques complémentaires" because they are both children of "Documents PCA"