update tmux.1 to reflect seven preset layouts

Index: tmux.1
===================================================================
RCS file: /cvs/src/usr.bin/tmux/tmux.1,v
retrieving revision 1.969
diff -u -p -r1.969 tmux.1
--- tmux.1	5 Nov 2024 21:07:19 -0000	1.969
+++ tmux.1	8 Nov 2024 08:53:24 -0000
@@ -369,7 +369,7 @@ Enter copy mode and scroll one page up.
 .It Left, Right
 Change to the pane above, below, to the left, or to the right of the current
 pane.
-.It M-1 to M-5
+.It M-1 to M-7
 Arrange panes in one of the seven preset layouts:
 even-horizontal, even-vertical,
 main-horizontal, main-horizontal-mirrored,