[groff] 04/16: pic(1): Explain what tpic was.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit bb6f68ce158d58d361e2c5786dbc039d9b0d3718
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Sat Oct 17 05:13:05 2020 +1100

    pic(1): Explain what tpic was.
    
    The origins of tpic seem to have rotted almost completely off of the
    Internet.  Explain what it was since we refer to it.
    
    squashme pic
---
 src/preproc/pic/pic.1.man | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/src/preproc/pic/pic.1.man b/src/preproc/pic/pic.1.man
index 9cc6f5d..d1d0d15 100644
--- a/src/preproc/pic/pic.1.man
+++ b/src/preproc/pic/pic.1.man
@@ -184,7 +184,7 @@ not to use zero-length lines to draw dots in troff mode.
 .TP
 .B \-c
 Be more compatible with
-.BR tpic .
+.IR tpic .
 .
 Implies
 .BR \-t .
@@ -324,15 +324,27 @@ instead of \ebox\egraph.
 .
 .
 .LP
-You must use a \*(tx driver that supports the
-.B tpic
-specials, version 2.
+You must use a \*[tx] driver that supports
+.I tpic
+version 2 specials.
+.
+.RI ( tpic
+was a fork of AT&T
+.I pic \" AT&T
+by Tim Morgan of the University of California at Irvine that diverged
+from its source around 1984.
+.
+It is best known today for lending its name to a group of
+.B \[rs]special
+commands it produced for \*[tx].)
+.\" http://ftp.cs.stanford.edu/tex/texhax/texhax90.019
 .
 .
 .LP
 Lines beginning with
 .B \e
-are passed through transparently; a
+are passed through transparently;
+a
 .B %
 is added to the end of the line to avoid unwanted spaces.
 .