-------------------
- Added translations for `can_not_unselect_plone_group_meetingconfig`.
[gbastien]
- Added translations related to only previewable annexes not duplicated.
[gbastien]
- Adapted `return_to_proposing_group` with validation WFA related translations.
Removed no more used `returned_to_proposing_group_with_validation_state`.
[gbastien]
- Overrided `collective.iconifiedcategory` translation of
`Show preview description.` to be more specific regarding `PloneMeeting`.
[gbastien]