bug#46298: 28.0.50; Best default for ispell-program-name

[Peter Oliver]

The default value of ispell-program-name is decided by looking in turn for the 
binaries aspell, ispell, hunspell and enchant-2, and using whichever is first 
found.  Would it make sense to sort these in order of which we believe to be 
best?

As I understand it, which backend is most accurate varies from language to 
language.  Assuming the quality of the Emacs integration is equal, I would 
suggest putting Enchant first on the list rather than last.  Enchant doesnʼt do 
any spellchecking itself, but instead selects a backend based on a per-language 
configuration preference, automatically skipping any backends which are not 
installed or for which dictionaries are not installed in the current language.

I notice that the Red Hat/Fedora packages patch Emacs to put Hunspell first on 
the list 
(https://src.fedoraproject.org/rpms/emacs/blob/rawhide/f/emacs-spellchecker.patch).
  The rationale for this was that if Aspell was installed but the Aspell 
dictionaries for a language were not, then ispell-buffer fails 
(https://bugzilla.redhat.com/show_bug.cgi?id=713600).  If, instead, Enchant was 
tried first, this kind of tinkering would not be necessary.

--
Peter Oliver