fix: displays fallback of default looks should be ':0'

// solution: changed from '0:' to ':0'

Signed-off-by: shane.xb.qian <shane.qian@foxmail.com>

bin/mailsync

@@ -43,7 +43,7 @@ case "$(uname)" in
 	displays="$(echo "$pgrepoutput" | grep -wo "[0-9]*:[0-9]\+" | sort -u)"
 	[ -z "$displays" ] && [ -d /tmp/.X11-unix ] && displays=$(cd /tmp/.X11-unix && for x in X*; do echo ":${x#X}"; done)
 
-	notify() { [ -n "$pgrepoutput" ] && for x in ${displays:-0:}; do
+	notify() { [ -n "$pgrepoutput" ] && for x in ${displays:-:0}; do
 			export DISPLAY="$x"
 			notify-send --app-name="mutt-wizard" "$1" "$2"
 		done ;}