代码示例错误

content/zh-cn/overview/mannual/java-sdk/reference-manual/protocol/triple.md#spring-web注解

示例代码是这样的：
```java
@RestController
@RequestMapping("/demo")
public interface DemoService {
@GetMapping(value = "/hello")
String sayHello();
}
```

在starter网站下载的demo项目中这样做会导致启动报错，`ambiguous bean` 这样的错误。
去掉 `@RestController` 注解后，启动正常。

同时在示例项目 https://github.com/apache/dubbo-samples/blob/master/2-advanced/dubbo-samples-triple-rest/dubbo-samples-triple-rest-springmvc/src/main/java/org/apache/dubbo/rest/demo/DemoService.java 中，也没有 `@RestController` 注解。

Open content/zh-cn/overview/mannual/java-sdk/reference-manual/protocol/triple.md and review the Spring Web annotation example around the cited section. Compare it with the linked dubbo-samples DemoService.java; done means the documentation example matches the working sample and no longer includes the annotation that causes the reported startup error.

Written by the indexing model from the issue text.