Equality hints that kind of work
by_equation fixed
Patterns working as expected.

This version first matches against the terms, ignoring the magenta
annotations, and then against the type. This gives the expected
behavior for most cases, it seems.
More exact matching of magenta
Remove use records
Minor cleanup.
Pattern matching can result in unequal terms.
Problematic example in `examples/nat.br`.
Deleted unwanted `foo.br`