bug#20741: 24.4; flyspell doesn't work with abbreviations ending in a period

[Eli Zaretskii <eliz@gnu.org>]

> From: Reuben Thomas <rrt@sc3d.org>
> Date: Sun, 13 Feb 2022 21:33:32 +0000
> Cc: Lars Ingebrigtsen <larsi@gnus.org>, 20741@debbugs.gnu.org
> 
>  Maybe we should have a list of exceptions?
> 
> As an upstream spellchecker maintainer, I don't think that's a good idea. Emacs should just be using the
> spellchecker. If it's not working, the problem should be fixed in the spellchecker.

I don't think I understand what this means in practice.  "Use the
spell-checker" how?  Do you mean we should not break words on
punctuation characters, or do you mean not to break them only on '.',
or do you mean something else?

Emacs is widely used to edit program sources, where stuff like
"file.attribute" and "list-my-packages" happens quite frequently.
Right now, these are not marked as misspellings, but if we pass them
to the speller with the punctuation, we are likely to get back
indications of misspelled words, which is not what we want.  Thus my
questions above: if we want to handle punctuation characters smarter
than just considering them part of the NOT-CASECHARS class, we need to
come up with a specification that will improve the situation, not make
it worse.  Can we do that?

> To be honest, I'm not sure Emacs can do much here.

I tend to agree, but maybe we can come up with some minor
improvements, even if they don't solve the problem in its entirety.