Follow-up the PR #4955, etc

・More ANALOG NUMBERING to Analog Input
・Add comment header to all the section of all the pins files

・Sort sections as follows:
1. Some special definitions (USBCON, LARGE_FLASH, etc)
2. Servos
3. Limit Switches
4. Z Probe
5. Steppers
6. Temperature Sensors
7. Heaters / Fans
8. Misc. Functions
9. LCD / Controller

・Move MAX6675_SS into "Temperature Sensors" section
・Adjust spacing

Marlin/pins_K8400.h

@@ -37,18 +37,31 @@
 
 #include "pins_3DRAG.h"
 
-#undef X_MAX_PIN
-#undef X_MIN_PIN
-#undef Y_MAX_PIN
-#undef Y_MIN_PIN
+//
+// Limit Switches
+//
 #define X_STOP_PIN  3
 #define Y_STOP_PIN 14
 
+#undef X_MIN_PIN
+#undef X_MAX_PIN
+#undef Y_MIN_PIN
+#undef Y_MAX_PIN
+
+//
+// Steppers
+//
 #undef E1_STEP_PIN
 #define E1_STEP_PIN   32
 
-#undef PS_ON_PIN
-#undef KILL_PIN
-
+//
+// Heaters / Fans
+//
 #undef HEATER_1_PIN
 #define HEATER_1_PIN  11
+
+//
+// Misc. Functions
+//
+#undef PS_ON_PIN
+#undef KILL_PIN