Update custom/script output on click events

I think it would be useful if the label of custom scripts were updated when the user clicks on them, with the text output of click-(left|ritgh|middle). This would make them feel more responsive, instead of the action being triggered and having to wait for the next iteration to see the result.

As an example, I have an script that displays which pulseaudio card I'm currently using, and cycles through them on click-left. However, the toggled card is not shown until the next regular call of the script, which is kinda annoying.