[groff] 06/12: [docs]: Document another AT&T troff difference.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 451705d95ada36c09317a0ec903ff43e366f1e29
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Fri Feb 2 18:58:10 2024 -0600

    [docs]: Document another AT&T troff difference.
    
    * doc/groff.texi (Other Differences):
    * man/groff_diff.7.man (Implementation differences): Do it.
    
    Exhibit:
    
    $ DWBHOME=. ./bin/nroff defeat-end-of-sentence-detection.roff|cat -s
    In the input, this  sentence  will  end  with  a  period  and  no
    trailing  space.   This  sentence  will  end  with a period and a
    trailing space. How did they set?
---
 doc/groff.texi       | 11 ++++++++++-
 man/groff_diff.7.man | 16 ++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/doc/groff.texi b/doc/groff.texi
index dce38736d..05eb8f913 100644
--- a/doc/groff.texi
+++ b/doc/groff.texi
@@ -464,7 +464,7 @@ Documentation License''.
 @title groff
 @subtitle The GNU implementation of @code{troff}
 @subtitle Edition 1.23.0+Git
-@subtitle January 2024
+@subtitle February 2024
 @author Trent@tie{}A.@: Fisher
 @author Werner Lemberg
 @author G.@tie{}Branden Robinson
@@ -17607,6 +17607,15 @@ GNU @code{troff} does not allow the use of the escape 
sequences
 does.  The @code{\A} escape sequence (@pxref{Identifiers}) may be
 helpful in avoiding use of these escape sequences in names.
 
+@cindex trailing space, on input lines, difference from @acronym{AT&T} 
@code{troff}
+@cindex space, trailing, on input lines, difference from @acronym{AT&T} 
@code{troff}
+@cindex end-of-sentence detection, cancellation, on @acronym{AT&T} @code{troff}
+@cindex sentence, cancelling detection of end of, on @acronym{AT&T} 
@code{troff}
+@acronym{AT&T} @command{troff} discards trailing spaces from input
+lines, like GNU @command{troff}, but if it does so, @acronym{AT&T}
+@command{troff} also cancels end-of-sentence detection.  Use of the
+dummy character escape sequence @code{\&} is more portable.
+
 @cindex adjustment to both margins, difference from @acronym{AT&T} @code{troff}
 @cindex rivers
 When adjusting to both margins, @acronym{AT&T} @code{troff} at first
diff --git a/man/groff_diff.7.man b/man/groff_diff.7.man
index ef294bdf4..3c3e96e52 100644
--- a/man/groff_diff.7.man
+++ b/man/groff_diff.7.man
@@ -5323,6 +5323,22 @@ are supported by other implementations.
 .
 .
 .P
+AT&T
+.I troff \" AT&T
+discards trailing spaces from input lines,
+like GNU
+.IR troff , \" GNU
+but if it does so,
+AT&T
+.I troff \" AT&T
+also cancels end-of-sentence detection.
+.
+Use of the dummy character escape sequence
+.B \[rs]&
+is more portable.
+.
+.
+.P
 When adjusting to both margins,
 AT&T
 .I troff \" AT&T