Fix missing backslash in macro

Marlin/pins.h

   #define Z_MIN_PIN          -1
 #endif
 
-#define SENSITIVE_PINS { 0, 1,
+#define SENSITIVE_PINS { 0, 1, \
                         X_STEP_PIN, X_DIR_PIN, X_ENABLE_PIN, X_MIN_PIN, X_MAX_PIN, \
                         Y_STEP_PIN, Y_DIR_PIN, Y_ENABLE_PIN, Y_MIN_PIN, Y_MAX_PIN, \
                         Z_STEP_PIN, Z_DIR_PIN, Z_ENABLE_PIN, Z_MIN_PIN, Z_MAX_PIN, Z_PROBE_PIN, \