absolute path on menu icon turns in 404 error

As the custom menu icon is called with an absolute path, it gives 404 error if you launch the website in a subfolder www.domain.com/drupal/

Just need to replace in toolbar_menu/css/toolbar_menu.module.css

.toolbar-bar .toolbar-icon-toolbar-menu:before {
  background-image: url(/core/misc/icons/bebebe/cog.svg);
}

by

.toolbar-bar .toolbar-icon-toolbar-menu:before {
  background-image: url(../../../../core/misc/icons/bebebe/cog.svg);
}

but as you can not ensure the module will be installed in the /modules/contrib/ folder, maybe it should be better to provide your own icon though the module or call it differently.

Thanks.