bug#21140: 25.0.50; Isearch "char-fold" by default

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: bruce.connor.am@gmail.com,  sva-news@mygooglest.com,  
> 21140@debbugs.gnu.org
> Date: Wed, 29 Jul 2015 01:21:45 +0300
> 
> >> In case of case-folding the parameter names used in isearch messages are:
> >> “case-sensitive” and “case-insensitive”.
> >>
> >> By analogy, can we use: “char-sensitive” and “char-insensitive”?
> >
> > I doubt that will be clear to users, since no one else calls this by
> > that name.  "Folding" is the accepted terminology, though perhaps
> > "char-fold" is also slightly unclear.  How about just "Fold"?
> 
> “Fold” is too broad.  “Char-fold” is more concise and seems is
> the accepted terminology, e.g.
> https://www.elastic.co/guide/en/elasticsearch/guide/current/character-folding.html
> http://userguide.icu-project.org/transforms/casemappings

"Character folding" or simply "folding" is accepted terminology.  But
"char-fold" is not, it's a confusing shorthand.  That's why I
suggested "fold", which is accepted terminology and is short.

> Or does Unicode.org have a better name?  I can find only this draft
> http://www.unicode.org/reports/tr30/tr30-4.html

Unicode uses "folding", see
http://unicode.org/reports/tr10/#Collation_Folding.