Put the MMU2 menu with the others

Marlin/src/feature/prusa_MMU2/mmu2.cpp

 #if ENABLED(PRUSA_MMU2)
 
 #include "mmu2.h"
-#include "mmu2_menu.h"
+#include "../../lcd/menu/menu_mmu2.h"
 
 MMU2 mmu2;
 

Marlin/src/gcode/feature/pause/M600.cpp

 #endif
 
 #if ENABLED(PRUSA_MMU2)
-  #include "../../../feature/prusa_MMU2/mmu2_menu.h"
+  #include "../../../lcd/menu/menu_mmu2.h"
 #endif
 
 /**

Marlin/src/lcd/menu/menu_main.cpp

 }
 
 #if ENABLED(PRUSA_MMU2)
-  #include "../../feature/prusa_MMU2/mmu2_menu.h"
+  #include "../../lcd/menu/menu_mmu2.h"
 #endif
 
 void menu_tune();

Marlin/src/feature/prusa_MMU2/mmu2_menu.cpp → Marlin/src/lcd/menu/menu_mmu2.cpp

 
 #if HAS_LCD_MENU && ENABLED(MMU2_MENUS)
 
-#include "mmu2.h"
-#include "mmu2_menu.h"
-#include "../../lcd/menu/menu.h"
+#include "../../feature/prusa_MMU2/mmu2.h"
+#include "menu_mmu2.h"
+#include "menu.h"
 
 uint8_t currentTool;
 bool mmuMenuWait;

Marlin/src/feature/prusa_MMU2/mmu2_menu.h → Marlin/src/lcd/menu/menu_mmu2.h

  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
-
 #pragma once
 
-#include "../../inc/MarlinConfig.h"
+#include <stdint.h>
 
-#if HAS_LCD_MENU && ENABLED(MMU2_MENUS)
-  extern void menu_mmu2();
-  extern void mmu2_M600();
-  extern uint8_t mmu2_chooseFilament();
-#endif
+extern void menu_mmu2();
+extern void mmu2_M600();
+extern uint8_t mmu2_chooseFilament();