The names weren't fully explicit in the elaborator, so ambiguity
resolution wasn't able to take advantage of type-directed pruning. Now
they're explicit (but hard-coded, which we should fix later...) so they
can be resolved more easily.
These are still to be updated (as noted in the files), but it needs
doing before any kind of preliminary release. Plan is to refresh the
tutorial and make sure samples work again, then write a more
comprehensive document explaining changes since Idris 1.
