Put constructor tags behind a reference in num-scott adt encoding

[developedby]

Currently, constructors are encoded using a numeric tag to differentiate between them:

type Option = (Some val) | None
# becomes
Option/Some = @val @x (x 0 val)
Option/None = @x (x 1)

This works well, but it's hard to disambiguate the result of a program.
Without changing behaviour, we could put each tag behind a unique reference, that way we still get their names at the end, and we could possibly use that to rebuild the constructors during readback.

type Option = (Some val) | None
# could be
Option/SOME = 0
Option/NONE = 1
Option/Some = @val @x (x Option/SOME val)
Option/None = @x (x Option/NONE)

This has the drawback of making pattern matching take 1 extra dereference interaction.