Undo PokeCodec's PRs

This commit undoes most of PokeCodec's PRs after the debate in chat. Some
harmless or completely superseded PRs have been left alone, as there is not
much benefit in attempting to undo them.

Reverts #1104, #1108, #1115, #1118, #1119, #1124, #1126, #1127, #1132, #1136,
#1137, #1139, #1140, #1144, #1148, #1149, #1150, #1153, #1155, #1177, #1179,
#1180, #1181, #1182 and #1183.

include/list_menu.h

@@ -24,7 +24,7 @@ struct ListMenu;
 struct ListMenuItem
 {
     const u8 *name;
-    u32 id;
+    s32 id;
 };
 
 struct ListMenuTemplate
@@ -98,7 +98,7 @@ struct CursorStruct
 extern struct ScrollArrowsTemplate gTempScrollArrowTemplate;
 extern struct ListMenuTemplate gMultiuseListMenuTemplate;
 
-u32 DoMysteryGiftListMenu(const struct WindowTemplate *windowTemplate, const struct ListMenuTemplate *listMenuTemplate, u8 arg2, u16 tileNum, u16 palNum);
+s32 DoMysteryGiftListMenu(const struct WindowTemplate *windowTemplate, const struct ListMenuTemplate *listMenuTemplate, u8 arg2, u16 tileNum, u16 palNum);
 u8 ListMenuInit(struct ListMenuTemplate *listMenuTemplate, u16 scrollOffset, u16 selectedRow);
 u8 ListMenuInitInRect(struct ListMenuTemplate *listMenuTemplate, struct ListMenuWindowRect *arg1, u16 scrollOffset, u16 selectedRow);
 s32 ListMenu_ProcessInput(u8 listTaskId);