Add 'sentence-end-double-space'.

If you prefer "lighter" punctuation and one space between sentences,
for example:

Mr and Mrs Jones are from the UK. They arrived today.

over more liberal use of full stops and double spaces between
sentences:

Mr. and Mrs. Jones are from the U.K.  They arrived today.

then toggling 'sentence-end-double-space' will make mg's
fill-paragraph function format text using one space instead of two
(the default) between sentences. However, be careful, should you have
a double spaced document and accidentally "format" it to have single
spaces, then you may have a problem. mg won't be able to revert the
formatting for you (unless you have a previous version of the text in
the "undo" history, or are using mg's backup facility and haven't
opened and saved multiple times!).

Comments from schwarze@

1 files changed, 6 insertions, 2 deletions

diff --git a/usr.bin/mg/mg.1 b/usr.bin/mg/mg.1
index e43c2798922..391abca2ec1 100644
--- a/usr.bin/mg/mg.1
+++ b/usr.bin/mg/mg.1
@@ -1,7 +1,7 @@
-.\"	$OpenBSD: mg.1,v 1.103 2016/03/17 21:56:12 lum Exp $
+.\"	$OpenBSD: mg.1,v 1.104 2016/04/14 17:05:32 lum Exp $
 .\" This file is in the public domain.
 .\"
-.Dd $Mdocdate: March 17 2016 $
+.Dd $Mdocdate: April 14 2016 $
 .Dt MG 1
 .Os
 .Sh NAME
@@ -838,6 +838,10 @@ If found, dot gets moved to just after the matched
 characters, if not found, print a message.
 .It self-insert-command
 Insert a character.
+.It sentence-end-double-space
+Toggle double or single spaces for end of sentences.
+Double is the default.
+Currently only affects fill-paragraph.
 .It set-case-fold-search
 Set case-fold searching, causing case not to matter
 in regular expression searches.