The .monkeys file is not touched: a project still lists the key, and
doctor reports it missing until someone stores a secret for it again.
A key that .monkeys holds as a value for the profile has its line deleted
instead, since the file says which of the two it is:
monkeys forget API_URL
forgot API_URL from .monkeys for @test
A value the file sets for several profiles together is refused, the way
set --public refuses it.
A profile on its own, with no key, forgets every secret stored under it, and a
comma list forgets several. The names are all resolved before anything is
deleted, so a typo in the second name leaves the first untouched:
Neither form touches .monkeys: a project still declares the
profile, and doctor reports every key of it missing. A bare @ is no profile
and is refused, so the secrets with no profile go one key at a time.