TWIG Issue

Problem/Motivation

Hi all,
I'm excited about this module. Thank you for all the hard work that's gone in to develop it.

One thing I do wish there was, was better TWIG support. It'd be nice to be able to theme the link and also to see a different class for when the button is subscribed or unsubscribed.

At the moment, the problem I'm noticing is that whenever I unsubscribe, a new paragraph tag wraps the tag, so if you subscribe and unsubscribe multiple times, it creates quite a chain of nested paragraphs.