modify example to verify .

spring-cloud-alibaba-examples/nacos-example/nacos-discovery-example/nacos-discovery-provider-example/src/main/java/org/springframework/cloud/alibaba/cloud/examples/ProviderApplication.java

@@ -13,7 +13,6 @@ import org.springframework.web.bind.annotation.RestController;
  * @author xiaojing
  */
 @SpringBootApplication
-@EnableDiscoveryClient
 public class ProviderApplication {
 
 	public static void main(String[] args) {

spring-cloud-alibaba-nacos-discovery/src/main/java/org/springframework/cloud/alibaba/nacos/NacosDiscoveryAutoConfiguration.java

@@ -41,7 +41,7 @@ import org.springframework.context.annotation.Configuration;
 @ConditionalOnNacosDiscoveryEnabled
 @ConditionalOnClass(name = "org.springframework.boot.web.servlet.context.ServletWebServerInitializedEvent")
 @ConditionalOnProperty(value = "spring.cloud.service-registry.auto-registration.enabled", matchIfMissing = true)
-@AutoConfigureAfter({ AutoServiceRegistrationAutoConfiguration.class })
+@AutoConfigureAfter(AutoServiceRegistrationAutoConfiguration.class)
 public class NacosDiscoveryAutoConfiguration {
 
 	@Bean