Update Italian language (#15373)

Marlin/src/lcd/language/language_it.h

 #define MSG_YES                             _UxGT("SI")
 #define MSG_NO                              _UxGT("NO")
 #define MSG_BACK                            _UxGT("Indietro")
+#define MSG_MEDIA_ABORTING                  _UxGT("Annullando...")
 #define MSG_MEDIA_INSERTED                  _UxGT("Media inserito")
 #define MSG_MEDIA_REMOVED                   _UxGT("Media rimosso")
 #define MSG_MEDIA_RELEASED                  _UxGT("Media rilasciato")
+#define MSG_MEDIA_WAITING                   _UxGT("Aspettando media")
+#define MSG_MEDIA_READ_ERROR                _UxGT("Err.leggendo media")
+#define MSG_MEDIA_USB_REMOVED               _UxGT("Dispos.USB rimosso")
+#define MSG_MEDIA_USB_FAILED                _UxGT("Avvio USB fallito")
 #define MSG_LCD_ENDSTOPS                    _UxGT("Finecor.") // Max 8 caratteri
 #define MSG_LCD_SOFT_ENDSTOPS               _UxGT("Finecorsa Soft")
 #define MSG_MAIN                            _UxGT("Menu principale")
 #define MSG_LEVEL_BED                       MSG_BED_LEVELING
 #define MSG_LEVEL_CORNERS                   _UxGT("Livella spigoli")
 #define MSG_NEXT_CORNER                     _UxGT("Prossimo spigolo")
+#define MSG_MESH_EDITOR                     _UxGT("Editor Mesh")
 #define MSG_EDIT_MESH                       _UxGT("Modifica Mesh")
 #define MSG_EDITING_STOPPED                 _UxGT("Modif. Mesh Fermata")
 #define MSG_PROBING_MESH                    _UxGT("Punto sondato")
 #define MSG_UBL_VALIDATE_MESH_MENU          _UxGT("Valida Mesh")
 #define MSG_UBL_VALIDATE_MESH_M1            _UxGT("Valida Mesh " PREHEAT_1_LABEL)
 #define MSG_UBL_VALIDATE_MESH_M2            _UxGT("Valida Mesh " PREHEAT_2_LABEL)
+#define MSG_G26_HEATING_BED                 _UxGT("G26 riscald.letto")
+#define MSG_G26_HEATING_NOZZLE              _UxGT("G26 riscald.ugello")
+#define MSG_G26_MANUAL_PRIME                _UxGT("Priming manuale...")
+#define MSG_G26_FIXED_LENGTH                _UxGT("Prime a lung.fissa")
+#define MSG_G26_PRIME_DONE                  _UxGT("Priming terminato")
+#define MSG_G26_CANCELED                    _UxGT("G26 Annullato")
+#define MSG_G26_LEAVING                     _UxGT("Uscita da G26")
 #define MSG_UBL_VALIDATE_CUSTOM_MESH        _UxGT("Valida Mesh pers.")
 #define MSG_UBL_CONTINUE_MESH               _UxGT("Continua Mesh")
 #define MSG_UBL_MESH_LEVELING               _UxGT("Livell. Mesh")
 #define MSG_UBL_NO_STORAGE                  _UxGT("Nessuna memoria")
 #define MSG_UBL_SAVE_ERROR                  _UxGT("Err: Salvataggio UBL")
 #define MSG_UBL_RESTORE_ERROR               _UxGT("Err: Ripristino UBL")
+#define MSG_UBL_Z_OFFSET                    _UxGT("Z-Offset: ")
 #define MSG_UBL_Z_OFFSET_STOPPED            _UxGT("Z-Offset Fermato")
 #define MSG_UBL_STEP_BY_STEP_MENU           _UxGT("UBL passo passo")
 
 #define MSG_INFO_PSU                        _UxGT("Alimentatore")
 #define MSG_DRIVE_STRENGTH                  _UxGT("Potenza Drive")
 #define MSG_DAC_PERCENT                     _UxGT("Driver %")
+#define MSG_ERROR_TMC                       _UxGT("ERR.CONNESSIONE TMC")
 #define MSG_DAC_EEPROM_WRITE                _UxGT("Scrivi DAC EEPROM")
 #define MSG_FILAMENT_CHANGE_HEADER_PAUSE    _UxGT("STAMPA IN PAUSA")
 #define MSG_FILAMENT_CHANGE_HEADER_LOAD     _UxGT("CARICA FILAMENTO")