Update part0b.md

Corrected the DOM function on explantion to reflect the actual code in main.js

Author: thiago4go

src/content/0/en/part0b.md

@@ -324,7 +324,7 @@ data.forEach(function(note) {
 Finally, the tree branch of the <em>ul</em> variable is connected to its proper place in the HTML tree of the whole page:
 
 ```js
-document.getElementsByClassName('notes').appendChild(ul)
+document.getElementById('notes').appendChild(ul)
 ```
 
 ### Manipulating the document object from console