Before, when two file types matched the same glob, the file type that
one was non-deterministic.
Now, "the more specific" file type wins. What this means is that we
break up the file by its extensions and prioritize the more literal glob
- If its just `*`, then its lowest priority
- If it contains `*` and other logic, then its next
- If it doesn't contain a `*`, then its the highest priority
This leaves out other glob syntax like `{one,two}` as those are
closed-ended and so considered specific still.
Fixes#487
