fix: 修改多个处理函数的返回类型为指针类型，以提高内存使用效率并避免不必要的拷贝

handler/echo/echo.go

@@ -11,11 +11,11 @@ func init() {
 	handler.RegisterHelpInform("echo", "echo", "echo <message> 再说一遍")
 }
 
-func echo(msg model.Message) (reply model.Reply) {
+func echo(msg model.Message) (reply *model.Reply) {
 	if len(msg.RawMsg) <= 5 {
-		return model.Reply{}
+		return &model.Reply{}
 	}
-	return model.Reply{
+	return &model.Reply{
 		ReplyMsg:       msg.RawMsg[5:],
 		ReferOriginMsg: true,
 		FromMsg:        msg,