dubbo:service Please add id or name property

[CJSoldier]

According to this line: https://github.com/apache/dubbo/blob/master/dubbo-config/dubbo-config-spring/src/main/java/org/apache/dubbo/config/spring/schema/DubboBeanDefinitionParser.java#L101

In fact, either id or name property is important for <dubbo:service>. When using group to distinguish different implementations but forgetting to configure both id and name property, I fail to invoke interface methods smoothly via jmeter. I have to add a number after interface name.

According to this line: https://github.com/apache/dubbo/blob/master/dubbo-config/dubbo-config-spring/src/main/java/org/apache/dubbo/config/spring/schema/DubboNamespaceHandler.java#L69

I understand that adding a number after a interface name is not requried when using dubbo:reference. It seems that quite a few people don't know these.