Removed trailing spaces in the most relevant files

Command used for the job:
egrep -rl ' $' --include *.c --include *.h --include  *.s --include  *.inc --include  *.txt *  | xargs sed -i 's/\s\+$//g'

Credits to Grant Murphy from Stack Overflow.

include/constants/item_effects.h

@@ -23,7 +23,7 @@
 #define ITEM3_POISON            0x10
 #define ITEM3_SLEEP             0x20
 #define ITEM3_LEVEL_UP          0x40
-#define ITEM3_GUARD_SPEC        0x80 // Works the same way as the move Mist.   
+#define ITEM3_GUARD_SPEC        0x80 // Works the same way as the move Mist.
 
 #define ITEM3_STATUS_ALL        (ITEM3_CONFUSION | ITEM3_PARALYSIS | ITEM3_FREEZE | ITEM3_BURN | ITEM3_POISON | ITEM3_SLEEP)