Update language_cz.h

New strings:
#define MSG_HALTED
#define MSG_PLEASE_RESET
Some texts shortened for smaller displays.

Marlin/language_cz.h

 #define MSG_BABYSTEP_Z                      "Babystep Z"
 #define MSG_ENDSTOP_ABORT                   "Endstop abort"
 #define MSG_HEATING_FAILED_LCD              "Chyba zahrivani"
-#define MSG_ERR_REDUNDANT_TEMP              "Chyba: REDUNDANTNI TEPLOTA"
+#define MSG_ERR_REDUNDANT_TEMP              "REDUND. TEPLOTA"
 #define MSG_THERMAL_RUNAWAY                 "TEPLOTNI SKOK"
-#define MSG_ERR_MAXTEMP                     "Chyba: VYSOKA TEPLOTA"
-#define MSG_ERR_MINTEMP                     "Chyba: NIZKA TEPLOTA"
-#define MSG_ERR_MAXTEMP_BED                 "Chyba: VYSOKA TEPLOTA PODL."
-#define MSG_ERR_MINTEMP_BED                 "Chyba: NIZKA TEPLOTA PODL."
+#define MSG_ERR_MAXTEMP                     "VYSOKA TEPLOTA"
+#define MSG_ERR_MINTEMP                     "NIZKA TEPLOTA"
+#define MSG_ERR_MAXTEMP_BED                 "VYS. TEPL. PODL."
+#define MSG_ERR_MINTEMP_BED                 "NIZ. TEPL. PODL."
+#define MSG_HALTED                          "TISK. ZASTAVENA"
+#define MSG_PLEASE_RESET                    "Provedte reset"
 #define MSG_END_HOUR                        "hod"
 #define MSG_END_MINUTE                      "min"
 #define MSG_HEATING                         "Zahrivani..."