sync with OpenBSD -current

usr.bin/tmux/tmux.1

@@ -1,4 +1,4 @@
-.\" $OpenBSD: tmux.1,v 1.935 2023/12/27 20:23:59 nicm Exp $
+.\" $OpenBSD: tmux.1,v 1.936 2024/02/13 08:10:23 nicm Exp $
 .\"
 .\" Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
 .\"
@@ -14,7 +14,7 @@
 .\" IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 .\" OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: December 27 2023 $
+.Dd $Mdocdate: February 13 2024 $
 .Dt TMUX 1
 .Os
 .Sh NAME
@@ -4023,10 +4023,20 @@ The value is the width and height separated by an
 character.
 The default is 80x24.
 .It Xo Ic destroy-unattached
-.Op Ic on | off
+.Op Ic off | on | keep-last | keep-group
 .Xc
-If enabled and the session is no longer attached to any clients, it is
-destroyed.
+If
+.Ic on ,
+destroy the session after the last client has detached.
+If
+.Ic off
+(the default), leave the session orphaned.
+If
+.Ic keep-last ,
+destroy the session only if it is in a group and has other sessions in that group.
+If
+.Ic keep-group ,
+destroy the session unless it is in a group and is the only session in that group.
 .It Xo Ic detach-on-destroy
 .Op Ic off | on | no-detached | previous | next
 .Xc