Document text window

include/help_message.h

@@ -1,6 +1,8 @@
 #ifndef GUARD_HELP_MESSAGE_H
 #define GUARD_HELP_MESSAGE_H
 
+extern const u8 gHelpMessageWindow_Gfx[];
+
 void DestroyHelpMessageWindow(u8 a0);
 u8 CreateHelpMessageWindow(void);
 void PrintTextOnHelpMessageWindow(const u8 * text, u8 mode);