server.go: format for

Signed-off-by: zhangxiaoyu-zidif <zhang.xiaoyu33@zte.com.cn>

api/server/server.go

@@ -92,13 +92,12 @@ func (s *Server) serveAPI() error {
 		}(srv)
 	}
 
-	for i := 0; i < len(s.servers); i++ {
+	for range s.servers {
 		err := <-chErrors
 		if err != nil {
 			return err
 		}
 	}
-
 	return nil
 }