[docs]: Further clarify end-of-sentence detection.

(One hopes.)

* doc/groff.texi (Sentences):
* man/roff.7 (Concepts): Do it.

Fixes <https://savannah.gnu.org/bugs/?64091>.  Thanks to Ingo Schwarze
and Dave Kemper for the report.

Also fix whitespace nit.  Thanks to Dave Kemper, he of the unflinching
osprey gaze.

3 files changed, 17 insertions, 6 deletions

diff --git a/ChangeLog b/ChangeLog
index a53ac4174..99ba97e00 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2023-04-22  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+	[docs]: Attempt to further clarify end-of-sentence detection.
+
+	* doc/groff.texi (Sentences):
+	* man/roff.7 (Concepts): Do it.
+
+	Fixes <https://savannah.gnu.org/bugs/?64091>.  Thanks to Ingo
+	Schwarze and Dave Kemper for the report.
+
 2023-04-14  G. Branden Robinson <g.branden.robinson@gmail.com>
 
 	[docs]: Minimally document `tag`, `taga` requests.
diff --git a/doc/groff.texi b/doc/groff.texi
index 948818ab7..b0ef7a91e 100644
--- a/doc/groff.texi
+++ b/doc/groff.texi
@@ -5010,9 +5010,9 @@ Welcome to groff.
 GNU @code{troff} does this by flagging certain characters (normally
 @samp{!}, @samp{?}, and @samp{.}) as potentially ending a sentence.
 When GNU @code{troff} encounters one of these @dfn{end-of-sentence
-characters} at the end of a line, or one of them is followed by two
-spaces on the same input line, it appends an inter-word space followed
-by an inter-sentence space in the formatted output.
+characters} at the end of an input line, or one of them is followed by
+two (unescaped) spaces on the same input line, it appends an inter-word
+space followed by an inter-sentence space in the formatted output.
 
 @Example
 R. Harper subscribes to a maxim of P. T. Barnum.
@@ -6388,7 +6388,7 @@ invalid input characters are @code{0x00}, @code{0x08}, @code{0x0B},
 @code{0x09}, @code{0x0B}, @code{0x0D}--@code{0x14},
 @code{0x17}--@code{0x1F}, and
 @code{0x30}--@code{0x3F}.@footnote{Historically, control characters like
-ASCII STX, ETX, and BEL (@key{Control+B},@key{ Control+C}, and
+ASCII STX, ETX, and BEL (@key{Control+B}, @key{Control+C}, and
 @key{Control+G}) have been observed in @code{roff} documents,
 particularly in macro packages employing them as delimiters with the
 output comparison operator to try to avoid collisions with the content
diff --git a/man/roff.7.man b/man/roff.7.man
index e0058e808..736afbc57 100644
--- a/man/roff.7.man
+++ b/man/roff.7.man
@@ -180,8 +180,9 @@ as potentially ending a sentence.
 .
 When the formatter encounters one of these
 .I end-of-sentence characters
-at the end of a line,
-or one of them is followed by two spaces on the same input line,
+at the end of an input line,
+or one of them is followed by two (unescaped) spaces on the same input
+line,
 it appends an inter-word space
 followed by an inter-sentence space in the formatted output.
 .