match: remove support for exact matching from main matcher class Exact matching is now handled by the exactmatcher class. We can safely remove _files from the __repr__() implementation, because even though the field is set, the patternspat field is enough for the representation to be unambiguous (which was not the case when the matcher could handle exact matches).

match: handle exact matching using new exactmatcher

merge: use intersectmatchers() in "m2-vs-ma optimization" It doesn't seem like this can actually happen, but seems like cleaner anyway.

match: handle includes using new intersectionmatcher