[groff] Mapping of \(bu to MIDDLE DOT

[Jeff Conrad]

Is there a reason that tty.tmac translates \(bu to \(pc or \(md
regardless of the output device or whether \(bu is available?

.ie c\[pc] \
.  tr \[bu]\[pc]
.el \
.  if c\[md] \
.    tr \[bu]\[md]

The only thing I can find on this is Ingo's message of 30 November 2015
("bullets render as question marks"); I agree with his statement
"Perhaps not the best possible choice."

Perhaps it makes sense for Tlatin1, which doesn't have a true bullet,
but it seems silly for Tutf8 (or my Tcp1252).  Even for Tlatin1, I'd
prefer an asterisk or even the age-old overstruck '+' and 'o'.  Isn't
the general rule for nroff to make the best possible visual
approximation when the true character isn't available?

In any event, for the general case, could we not do

.if !c\[bu] \{\
.  ie c\[pc] \
.    tr \[bu]\[pc]
.  el \
.    if c\[md] \
.      tr \[bu]\[md]
.\}

Jeff