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

[Paul Eggert]

Eli Zaretskii wrote:
> And using --disable-encoding is a simpler way of achieving
> that, as it doesn't need any postprocessing.

No, because we can't assume  that the installer has 'makeinfo'
and can run 'makeinfo' with --disable-encoding.  Instead, we must use
universally-available tools like 'sed' when installing.

> we should at least fix the handful of manuals that already use
> "@documentencoding utf-8", or use non-ASCII characters without any
> @documentencoding, thus producing Info files that might display
> incorrectly in certain locales.

None of that would fix the regression that Drew Adams noted.
Better would be to leave the files alone, and build the next
Emacs tarball with Texinfo 4.  We can switch to Texinfo 5 for
building tarballs after the feature freeze is over.