Melzi, comments cleanup

Marlin/src/core/boards.h

 
 #define _MB_1(B)  (defined(BOARD_##B) && MOTHERBOARD==BOARD_##B)
 #define MB(V...)  DO(MB,||,V)
-
-#define IS_MELZI MB(MELZI, MELZI_CREALITY, MELZI_MAKR3D, MELZI_MALYAN, MELZI_TRONXY, MELZI_V2)

Marlin/src/inc/SanityCheck.h

 #if !HAS_HEATER_0 && EXTRUDERS
   #error "HEATER_0_PIN not defined for this board."
 #elif !ANY_PIN(TEMP_0, MAX6675_SS)
-  #error "TEMP_0_PIN not defined for this board."
+  #error "TEMP_0_PIN or MAX6675_SS not defined for this board."
 #elif ((defined(__AVR_ATmega644P__) || defined(__AVR_ATmega1284P__)) && !PINS_EXIST(E0_STEP, E0_DIR))
   #error "E0_STEP_PIN or E0_DIR_PIN not defined for this board."
 #elif ( !(defined(__AVR_ATmega644P__) || defined(__AVR_ATmega1284P__)) && (!PINS_EXIST(E0_STEP, E0_DIR) || !HAS_E0_ENABLE))

Marlin/src/pins/lpc1768/pins_BTT_SKR_common.h

   #error "Oops! Make sure you have the LPC1768 environment selected in your IDE."
 #endif
 
-// If you have the Big tree tech driver expantion module, enable HAS_BTT_EXP_MOT
+// If you have the Big tree tech driver expansion module, enable HAS_BTT_EXP_MOT
 // https://github.com/bigtreetech/BTT-Expansion-module/tree/master/BTT%20EXP-MOT
 //#define HAS_BTT_EXP_MOT 1
 

Marlin/src/pins/sanguino/pins_MELZI.h

   #define BOARD_INFO_NAME "Melzi"
 #endif
 
+#define IS_MELZI 1
+
 #include "pins_SANGUINOLOLU_12.h"