By having the `pp.proofs` feature use `⋯` when omitting proofs, when
users copy/paste terms from the InfoView the elaborator can give an
error message explaining why the term cannot be elaborated.
Also adds `pp.proofs.threshold` option to allow users to pretty print
shallow proof terms. By default, only atomic proof terms are pretty
printed.
This adjustment was suggested in PR #3201, which added `⋯` and the
related `pp.deepTerms` option.
stop as soon as `lhs` and `rhs` are definitionally equal, and avoid
unnecessary case analysis.
This commit fixes the last issue exposed by #1074fixes#1074
