[groff] modernize -T ascii rendering of opening single quote

[Mike Bianchi]

> ... that doesn't look like a consensus yet, and unfortunately,
> i don't see how to argue further, ...
>       :
> Any ideas how to resolve this clash of priorities?

Rephrasing what I said before:
        ... build a generalize tool where the choice of font or device implies
        a set of desirable (to me) character substitutions and renderings that
        can easily be changed via a personalized configuration file.  Say
           .grofftool-txt.rc
        where  txt  is a font name or dev (or both?).

Some history here ...
The issue of how a specific a ASCII code is rendered goes back to >before<
troff.  In the 1970s (my youth) there were so-called "daisy wheel"
printers/typewriters/terminals where the font was implemented via an easily
substitutable part.
        en.wikipedia.org/wiki/Daisy_wheel_printing

The IBM Selectric "ball" (88 glyphs) served the same purpose.
        en.wikipedia.org/wiki/IBM_Selectric_typewriter

They were quite popular in the days of nroff.
So the question of how the single and double quotes would be printed was
answered by the specific typing element in the machine at the time of printing.
Programmers had their favorites; document writers theirs.

-- 
 Mike Bianchi