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.
spell-fu lacks support for multiple dictionaries, affix expansion, and
many non-English dictionaries, so I've added back flyspell support to
the spell module, but opt-in, because it is still the significantly
slower option and spell-fu may support them one day.
If not, tlikonen/wcheck-mode is another alternative to consider.
Fixes#3813
Aspell is a hard dependency of this module, even if you use hunspell as
a backend. The spellchecker will simply bow out if aspell isn't present
on your system at startup.
