Investigate and Fix Citations with Parentheses like XX Pac. (2d) XX

[mlissner]

I don't know how the citator would handle these presently, but in freelawproject/reporter-db#9 we discovered that there a number of citations in the corpus like:

XX Pac. (2d) XX

We need to identify:

1. Does the citator already capture these? My guess is no.
2. If it doesn't capture these, do they need to be added to the variations dictionary, or does the parser need to updated?

Naturally, we'll want some tests for these as well so that we capture them in the future too.

[mlissner]

This one is tricky. It could just be Pac. where we have citations like this. Or it could be widespread. If the latter, ugh. If the former, this is probably fairly easy.