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

[Drew Adams]

I don't see a change from `...' to '...' in this recent build:

In GNU Emacs 24.4.50.1 (i686-pc-mingw32)
 of 2014-04-29 on ODIEONE
Bzr revision: 117031 monnier@iro.umontreal.ca-20140429151607-qnkgbymwfaj5ut08
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/Devel/emacs/snapshot/trunk
 --enable-checking=yes,glyphs 'CFLAGS=-O0 -g3'
 LDFLAGS=-Lc:/Devel/emacs/lib 'CPPFLAGS=-DGC_MCHECK=1
 -Ic:/Devel/emacs/include''

But I've had a report from an info+.el user that his 24.4.50.1
build breaks the Info+ highlighting of names because '...' is
used now instead of `...'.  Dunno whether he has control over
the generation of Info files from Texinfo.

AFAIK, there is no way, from Emacs Lisp, to know whether an Info
file has been built to use '...' or `...'.  Is that correct?

IIUC, at Info build time there is a setting, @documentencoding,
that determines this.  In any case, Texinfo must somehow know
which pattern is being used for Info.

Request: Could we please have this information transmitted to
the resulting Info files somehow, so that it could be obtained
by Lisp code?

It would be much better, for instance, for the info+.el code
to use one or the other pattern for highlighting than it would
be to try to highlight both in the same file, just to catch the
appropriate one.