move poll to its own function to prep for track_anything.sh

scripts/track_volume

@@ -1,7 +1,11 @@
 #!/bin/sh
 
+poll() {
+  pamixer --get-volume | grep -E '^[0-9]+$'
+}
+
 pactl subscribe | while read -r ;do
   case "$REPLY" in
-    *change*)  pamixer --get-volume | grep -E '^[0-9]+$';;
+    *change*)  poll ;;
   esac
 done