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.
Was missing a 0 (a typo), which meant it was less than its default
value, thus having the opposite effect and making data loss *more*
likely.
Also got rid of outdated comments; I think those have been around since
the sub-v2.0 days of Doom.
Emacs generates long file names for auto-save and backup files.
undo-fu-session and tramp are two more big offenders. This fix SHA1s
their file names so they never exceed 40 characters.
Will also affect any package that uses make-backup-file-name-1
directly (like undo-tree).
