Update French localization (#4611)
* Update French localization
* minor fix
* `pack de démarrage` --> `kit de démarrage`
* Apply suggestions from code review
Co-authored-by: Stanislas Signoud <signez@stanisoft.net>
* Apply suggestions from @Signez code review
* Update messages.po
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Co-authored-by: Stanislas Signoud <signez@stanisoft.net>
authored by