update feature service page

Author: Jiayue Hu (Beyondsoft Consulting Inc)

docs-ref-services/container-service.md

@@ -43,6 +43,7 @@ msRestAzure.interactiveLogin().then((creds) => {
   console.log('An error ocurred:');
   console.dir(err, {depth: null, colors: true});
 });
+```
 
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