Add HAS_TEMP_HOTEND define

Marlin/Conditionals.h

 
   #define HAS_MOTOR_CURRENT_PWM (PIN_EXISTS(MOTOR_CURRENT_PWM_XY) || PIN_EXISTS(MOTOR_CURRENT_PWM_Z) || PIN_EXISTS(MOTOR_CURRENT_PWM_E))
 
+  #define HAS_TEMP_HOTEND (HAS_TEMP_0 || ENABLED(HEATER_0_USES_MAX6675))
+
   /**
    * Helper Macros for heaters and extruder fan
    */

Marlin/Marlin.h

   extern void digipot_i2c_init();
 #endif
 
-#if HAS_TEMP_0 || HAS_TEMP_BED || ENABLED(HEATER_0_USES_MAX6675)
+#if HAS_TEMP_HOTEND || HAS_TEMP_BED
   void print_heaterstates();
 #endif
 

Marlin/Marlin_main.cpp

   if (print_job_stop()) LCD_MESSAGEPGM(WELCOME_MSG);
 }
 
-#if HAS_TEMP_0 || HAS_TEMP_BED || ENABLED(HEATER_0_USES_MAX6675)
+#if HAS_TEMP_HOTEND || HAS_TEMP_BED
 
   void print_heaterstates() {
-    #if HAS_TEMP_0 || ENABLED(HEATER_0_USES_MAX6675)
+    #if HAS_TEMP_HOTEND
       SERIAL_PROTOCOLPGM(" T:");
       SERIAL_PROTOCOL_F(degHotend(target_extruder), 1);
       SERIAL_PROTOCOLPGM(" /");
 inline void gcode_M105() {
   if (setTargetedHotend(105)) return;
 
-  #if HAS_TEMP_0 || HAS_TEMP_BED || ENABLED(HEATER_0_USES_MAX6675)
+  #if HAS_TEMP_HOTEND || HAS_TEMP_BED
     SERIAL_PROTOCOLPGM(MSG_OK);
     print_heaterstates();
-  #else // !HAS_TEMP_0 && !HAS_TEMP_BED
+  #else // !HAS_TEMP_HOTEND && !HAS_TEMP_BED
     SERIAL_ERROR_START;
     SERIAL_ERRORLNPGM(MSG_ERR_NO_THERMISTORS);
   #endif
     now = millis();
     if (now > next_temp_ms) { //Print temp & remaining time every 1s while waiting
       next_temp_ms = now + 1000UL;
-      #if HAS_TEMP_0 || HAS_TEMP_BED || ENABLED(HEATER_0_USES_MAX6675)
+      #if HAS_TEMP_HOTEND || HAS_TEMP_BED
         print_heaterstates();
       #endif
       #ifdef TEMP_RESIDENCY_TIME

Marlin/temperature.cpp

     }
     // Every 2 seconds...
     if (ms > temp_ms + 2000) {
-      #if HAS_TEMP_0 || HAS_TEMP_BED || ENABLED(HEATER_0_USES_MAX6675)
+      #if HAS_TEMP_HOTEND || HAS_TEMP_BED
         print_heaterstates();
         SERIAL_EOL;
       #endif
     WRITE_HEATER_ ## NR (LOW); \
   }
 
-  #if HAS_TEMP_0 || ENABLED(HEATER_0_USES_MAX6675)
+  #if HAS_TEMP_HOTEND
     setTargetHotend(0, 0);
     soft_pwm[0] = 0;
     WRITE_HEATER_0P(LOW); // Should HEATERS_PARALLEL apply here? Then change to DISABLE_HEATER(0)