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

[Paul Eggert]

Eli Zaretskii wrote:
> Not necessarily.  I'm talking again about the Unicode characters
> produced by Texinfo 5 when @documentencoding says utf-8.  Any user can
> bump into this.

A user won't bump into that in the released Emacs manual, if
we build it with Texinfo 4.  The only people who will bump
into that are people who edit the manual and run Texinfo themselves.
These are few enough and expert enough that we can simply ask
them to use Texinfo 4 if they care about the quoting and don't
want to work on the trunk.