Fix typo in French translation

src/components/Letter.vue

@@ -95,9 +95,9 @@ export default {
         collection: 'collection',
         author: 'auteur(e)',
         recipient: 'destinataire',
-        gender: 'sex',
+        gender: 'sexe',
         date: 'date',
-        place: 'lieur',
+        place: 'lieu',
         stamp: 'tampon'
       }
     }