Put ChatEvent handler into own function

Comply with line limit.

src/server.h

@@ -476,6 +476,8 @@ private:
 	void DeleteClient(u16 peer_id, ClientDeletionReason reason);
 	void UpdateCrafting(Player *player);
 
+	void handleChatInterfaceEvent(ChatEvent *evt);
+
 	// This returns the answer to the sender of wmessage, or "" if there is none
 	std::wstring handleChat(const std::string &name, const std::wstring &wname,
 		const std::wstring &wmessage,