Design: mobile icon for seeing table of contents is unclear

[nielsbom]

The icon used here (the one on the left) is often used to fullscreen something. See: https://fontawesome.com/v3.2.1/icon/fullscreen

Can we instead use something like: https://fontawesome.com/v3.2.1/icon/list ?

I couldn't find the place in the code where this icon/image is set. If someone can point me to it I'll make a PR.

[kevinsimper]

@nielsbom I think it is define in the framework that ReasonML docs uses which is Docusaurus :) https://docusaurus.io/

But I agree, it is a bit atypical icon to use.