Handle pseudo elements like :before

[TheJaredWilcurt]

We're handling psuedo classes already (.thing:hover), but not psuedo elements (.thing:before).

Probably something like this:

.cow {
    padding: 10px;
}
.cow:before {
    content: '';
    background: #F00;
}

.rp__padding__--COLON10px { padding: 10px }
.rp__content__--COLON__--SINGLEQUOTE__--SINGLEQUOTE___--BEFORE:before { content: '' }
.rp__background__--COLON__--OCTOTHORPF00___--BEFORE:before { background: #F00 }

.rp__a { padding: 10px }
.rp__b:before { content: '' }
.rp__c:before { background: #F00 }

Should support all pseudo elements

• https://developer.mozilla.org/en-US/docs/Web/CSS/Pseudo-elements