Reorganize includes and declarations

Marlin/src/lcd/menu/menu_temperature.cpp

@@ -35,6 +35,10 @@
   #include "../../module/motion.h"
 #endif
 
+// Initialized by settings.load()
+int16_t lcd_preheat_hotend_temp[2], lcd_preheat_bed_temp[2];
+uint8_t lcd_preheat_fan_speed[2];
+
 //
 // "Temperature" submenu items
 //