bug#24056: `DATA and 'DATA look the same in Guile INFO in emacs on tty & X11

[myglc2]

Hello Guile,

You probably already know this, but, when viewing the Guile INFO on
emacs in tty or X11, the "Expression Syntax" part of the manual reads:

[...]
(quote DATA)
’DATA
[...]
(quasiquote DATA)
‘DATA
[...]

That is, the 'DATA and `DATA examples are both typeset with single
quote.

Upshot: One looks at things that are identical when one first reads how
they differ and wonders if one is going blind ;-)

I guess this is a problem with how @itemx handles backquote on these
platforms because the ./ref/api-evaluation.texi has a backquote ...

@itemx address@hidden

... and is correctly typeset in the HTML doc.

Anyway, maybe the 'DATA & `DATA examples could be marked up differently
to overcome this?