[notification] introduce an official `notify_on_commit` function
It provides a proper notification api instead of replacing it by yet another
clumsy one.
Closes #2837251
$(document).ready(function() {
$('a.rhythm').click(function (event){
$('div#pageContent').toggleClass('rhythm_bg');
$('div#page').toggleClass('rhythm_bg');
event.preventDefault();
});
});