Board Thread:Support Requests - Getting Started/@comment-36983971-20190521073506/@comment-957747-20190521163232

Using JS to alter that menu is against the Customization policy. However, you can use unicode "images". (Google "unicode images".) Since they are just text, they are allowed.

As Spongebob said though, do not change the text to just unicode images as the menu should be as straight forward as you can make it for a better user experience.