Review comments and documentation

include/trade.h

@@ -5,7 +5,7 @@ extern struct MailStruct gLinkPartnerMail[6];
 extern u8 gSelectedTradeMonPositions[2];
 
 extern const u16 gUnknown_826601C[];
-void sub_804C718(void);
+void CB2_ReturnFromLinkTrade(void);
 s32 sub_804FB34(void);
 
 #endif //GUARD_TRADE_H