bug#31344: additional note: error triggers due to flyspell package using the extra chars regexp

[Daniel Pittman]

Sorry, I forgot to mention in my original post that `flyspell-buffer` is
the trigger for this; it uses the extra character regular expression.  I
have not verified if it can be reproduced with only ispell.el commands,
though I assume it must be possible; it will trigger anywhere that regexp
is used.