bug#16292: 24.3.50; info docs now contain single straight quotes instead of `'

[Paul Eggert]

Eli Zaretskii wrote:

> (names of people) so using Latin-1 doesn't hamper users'
> ability to read the manual in any way

Most of the non-ASCII words are people's names, but many are not,
and often ASCIIfying these would hurt the manual.
These include symbols (e.g., "¬"), examples of encoding
("@samp{Naïve} is encoded as @samp{=?iso-8859-1?q?Na=EFve?=}"),
calendars ("Bahá'í"), the names of GNU programs ("真 Gnus"),
and configuration examples ("écrit" in email configuration).

Nowadays, on GNUish and POSIXish systems in the Emacs target
audience, there's more usage of UTF-8 than of Latin-1.  On
Ubuntu and Fedora, for example, the default locale for US
English is en_US.utf8.  Hence, converting info files to
Latin-1 would hurt standalone info users in the typical
setup on GNUish and POSIXish platforms.

Perhaps Microsoft Windows users are different, and typically
use Latin-1 or some other unibyte encoding.  If so, then
until standalone 'info' is improved we can support those
users by converting the info files on Windows platforms,
before installing the files.  Perhaps this could be a
configure-time option.  Or, perhaps it's simpler to ask
these folks to use Emacs to read their info files for now.

In any event we shouldn't convert the manual source to
Latin-1; not only would this lose information, it would hurt
the typical standalone info use case on GNUish systems.

In the short run, we do need to add @documentencoding
directives to the manuals that are already using UTF-8,
since makeinfo is currently mishandling these manuals.
This isn't critical for the plain-ASCII manuals, and we
could defer changes to the plain-ASCII manuals to the next
version of Emacs if necessary, though I expect it's better
to format all the manuals consistently.