Update article.md

Author: HannaParsa

2-ui/99-ui-misc/01-mutation-observer/article.md

@@ -15,7 +15,7 @@
 let observer = new MutationObserver(callback);
 ```
 
-And then attach it to a DOM node:
+و بعد observer را به DOM node، attach  می کند.
 
 ```js
 observer.observe(node, config);