featurep! will be renamed modulep! in the future, so it's been
deprecated. They have identical interfaces, and can be replaced without
issue.
featurep! was never quite the right name for this macro. It implied that
it had some connection to featurep, which it doesn't (only that it was
similar in purpose; still, Doom modules are not features). To undo such
implications and be consistent with its namespace (and since we're
heading into a storm of breaking changes with the v3 release anyway),
now was the best opportunity to begin the transition.
doom-enlist is now a deprecated alias for ensure-list, which is built
into Emacs 28.1+ and is its drop-in replacement. We've already
backported it for 27.x users in doom-lib (in 4bf4978).
Ref: 4bf49785fd
