fix: turn off synchronize-panes only on fzf-tmux pane

Similar reason to 482fd2b (fix: turn off remain-on-exit only on fzf-tmux
pane, 2023-08-24).

	Limit scope on which option is set to bare minimum.

Have confirmed this will not feed input back to other panes which are
set to be synchronized. However, note that this will not stop `fzf-tmux`
from being launched by two synchronized panes in parallel.

Link: #3397 (comment)

bin/fzf-tmux

@@ -151,9 +151,9 @@ argsf="${TMPDIR:-/tmp}/fzf-args-$id"
 fifo1="${TMPDIR:-/tmp}/fzf-fifo1-$id"
 fifo2="${TMPDIR:-/tmp}/fzf-fifo2-$id"
 fifo3="${TMPDIR:-/tmp}/fzf-fifo3-$id"
-if tmux_win_opts=$(tmux show-options -p remain-on-exit \; show-options -w synchronize-panes 2> /dev/null); then
-  tmux_win_opts=( $(sed '/ off/d; s/synchronize-panes/set-option -w synchronize-panes/; s/remain-on-exit/set-option -p remain-on-exit/; s/$/ \\;/' <<< "$tmux_win_opts") )
-  tmux_off_opts='; set-option -w synchronize-panes off ; set-option -p remain-on-exit off'
+if tmux_win_opts=$(tmux show-options -p remain-on-exit \; show-options -p synchronize-panes 2> /dev/null); then
+  tmux_win_opts=( $(sed '/ off/d; s/synchronize-panes/set-option -p synchronize-panes/; s/remain-on-exit/set-option -p remain-on-exit/; s/$/ \\;/' <<< "$tmux_win_opts") )
+  tmux_off_opts='; set-option -p synchronize-panes off ; set-option -p remain-on-exit off'
 else
   tmux_win_opts=( $(tmux show-window-options remain-on-exit \; show-window-options synchronize-panes | sed '/ off/d; s/^/set-window-option /; s/$/ \\;/') )
   tmux_off_opts='; set-window-option synchronize-panes off ; set-window-option remain-on-exit off'