yt-dlp-ntfy: mention PID when already running

yt-dlp-ntfy.sh

@@ -5,8 +5,8 @@ set -ueo pipefail
 PID_FILE="/tmp/yt-dlp-ntfy.pid"
 
 # Check if the script is already running
-if [ -e "$PID_FILE" ] && kill -0 $(cat "$PID_FILE"); then
+if [ -e "$PID_FILE" ] && kill -0 $(cat "$PID_FILE") &>/dev/null; then
-    echo "Script is already running. Exiting."
+    echo "Script is already running as PID $(cat $PID_FILE). Exiting."
     exit 1
 fi