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
+ Fixes ispell not noticing allowed words in your personal dictionary.
So +spell/correct would sometimes correct words that spell-fu wasn't
highlighting as incorrect, and sometimes wouldn't correct words that
were.
+ Fixes spell-fu refusing to read or write to the personal dictionary if
the file didn't already exist beforehand (for zq and zw).
+ Change ispell-dictionary fallback from "en_US" (which aspell won't
always recognize) to "en".
+ Moved ispell-personal-dictionary to ~/.emacs.d/.local/etc/ispell/ by
default.
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.
Spell-fu is significantly faster, but does produce more false
positives (more faces must be added to spell-fu-faces-exclude to reduce
these).
Unfortunately, there is no fancy "correction" interface for spell-fu
yet, so we'll have to resort to ispell-word (on z=) for now.
yaml-mode is derived from text-mode, rather than prog or conf-mode. This
may be true for other major modes, so we must be more judicious about
where we activate flyspell-mode.
