Add handling of BLTouch error state

Marlin/Marlin_main.cpp

     // Make room for probe
     do_probe_raise(_Z_PROBE_DEPLOY_HEIGHT);
 
+    // Check BLTOUCH probe status for an error
+    #if ENABLED(BLTOUCH)
+      if (servo[Z_ENDSTOP_SERVO_NR].read() == BLTouchState_Error) { stop(); return true; }
+    #endif
+
     #if ENABLED(Z_PROBE_SLED)
       if (axis_unhomed_error(true, false, false)) { stop(); return true; }
     #elif ENABLED(Z_PROBE_ALLEN_KEY)

Marlin/enum.h

   };
 #endif
 
+#if ENABLED(BLTOUCH)
+  enum BLTouchState {
+    BLTouchState_Deploy   = 10,
+    BLTouchState_Stow     = 90,
+    BLTouchState_Selftest = 120,
+    BLTouchState_Error    = 160
+  };
+#endif
+
 #if ENABLED(FILAMENT_CHANGE_FEATURE)
   enum FilamentChangeMenuResponse {
     FILAMENT_CHANGE_RESPONSE_WAIT_FOR,

Marlin/language_en.h

 #ifndef MSG_ZPROBE_OUT
   #define MSG_ZPROBE_OUT                      "Z probe out. bed"
 #endif
+#ifndef MSG_RESET_BLTOUCH
+  #define MSG_RESET_BLTOUCH                   "Reset BLTouch"
+#endif
 #ifndef MSG_HOME
   #define MSG_HOME                            "Home"  // Used as MSG_HOME " " MSG_X MSG_Y MSG_Z " " MSG_FIRST
 #endif

Marlin/ultralcd.cpp

 #include "configuration_store.h"
 #include "utility.h"
 
+#if ENABLED(BLTOUCH)
+  #include "servo.h"
+  extern Servo servo[NUM_SERVOS];
+#endif
+
 #if ENABLED(PRINTCOUNTER)
   #include "printcounter.h"
   #include "duration_t.h"
   static void lcd_main_menu() {
     START_MENU();
     MENU_ITEM(back, MSG_WATCH);
+
+    #if ENABLED(BLTOUCH)
+      if (servo[Z_ENDSTOP_SERVO_NR].read() == BLTouchState_Error)
+        MENU_ITEM(gcode, MSG_RESET_BLTOUCH, "M280 S90 P" STRINGIFY(Z_ENDSTOP_SERVO_NR));
+    #endif
+
     if (planner.movesplanned() || IS_SD_PRINTING) {
       MENU_ITEM(submenu, MSG_TUNE, lcd_tune_menu);
     }