Correct some FR strings

Co-Authored-By: pipersw <pipersw@users.noreply.github.com>

Marlin/src/lcd/language/language_fr.h

 #define MSG_PREHEAT_1                       _UxGT("Préchauffage PLA")
 #define MSG_PREHEAT_1_N                     _UxGT("Préchauff. PLA ")
 #define MSG_PREHEAT_1_ALL                   _UxGT("Préch. PLA Tout")
-#define MSG_PREHEAT_1_END                   MSG_PREHEAT_1 _UxGT(" fini")
+#define MSG_PREHEAT_1_END                   MSG_PREHEAT_1 _UxGT(" buse")
 #define MSG_PREHEAT_1_BEDONLY               _UxGT("Préch. PLA lit")
 #define MSG_PREHEAT_1_SETTINGS              _UxGT("Régl. prech. PLA")
 #define MSG_PREHEAT_2                       _UxGT("Préchauffage ABS")
 #define MSG_PREHEAT_2_N                     _UxGT("Préchauff. ABS ")
 #define MSG_PREHEAT_2_ALL                   _UxGT("Préch. ABS Tout")
-#define MSG_PREHEAT_2_END                   MSG_PREHEAT_2 _UxGT(" fini")
+#define MSG_PREHEAT_2_END                   MSG_PREHEAT_2 _UxGT(" buse")
 #define MSG_PREHEAT_2_BEDONLY               _UxGT("Préch. ABS lit")
 #define MSG_PREHEAT_2_SETTINGS              _UxGT("Régl. prech. ABS")
 #define MSG_COOLDOWN                        _UxGT("Refroidir")