update comment for "dynamic" field (#3900)

update comment for "dynamic" field

dubbo-config/dubbo-config-api/src/main/java/org/apache/dubbo/config/AbstractServiceConfig.java

@@ -71,8 +71,8 @@ public abstract class AbstractServiceConfig extends AbstractInterfaceConfig {
     protected String document;
 
     /**
-     * Whether to register as a dynamic service or not on register center, it the value is false, the status will be disabled
-     * after the service registered,and it needs to be enabled manually; if you want to disable the service, you also need
+     * Whether to register as a dynamic service or not on register center, the value is true, the status will be enabled
+     * after the service registered,and it needs to be disabled manually; if you want to disable the service, you also need
      * manual processing
      */
     protected Boolean dynamic = true;