Correct usage of MysteryEvent to MysteryGift

include/constants/mystery_gift.h

@@ -1,5 +1,5 @@
-#ifndef GUARD_CONSTANTS_MEVENT_H
-#define GUARD_CONSTANTS_MEVENT_H
+#ifndef GUARD_CONSTANTS_MYSTERY_GIFT_H
+#define GUARD_CONSTANTS_MYSTERY_GIFT_H
 
 #define GET_NUM_STAMPS        0
 #define GET_MAX_STAMPS        1
@@ -44,4 +44,4 @@
 
 #define WONDER_CARD_FLAG_OFFSET 1000
 
-#endif //GUARD_MEVENT_H
+#endif //GUARD_CONSTANTS_MYSTERY_GIFT_H