I'd like to provide an alternate, easier solution that is specific to FontAwesome. If you're using a different iconic font, JOPLOmacedo's answer is still perfectly fine for use.
FontAwesome now handles list styles internally with CSS classes.
Here's the official example:
<ul class="fa-ul">
<li><span class="fa-li"><i class="fas fa-check-square"></i></span>List icons can</li>
<li><span class="fa-li"><i class="fas fa-check-square"></i></span>be used to</li>
<li><span class="fa-li"><i class="fas fa-spinner fa-pulse"></i></span>replace bullets</li>
<li><span class="fa-li"><i class="far fa-square"></i></span>in lists</li>
</ul>