Add a warning to "automatic suspend" setting

We'll want to enable system sleep (suspend to ram) via systemd again which will make the "Automatic suspend" setting in g-c-c visible again.

Can we add a (possibly colored) warning to this that says "Experimental - use at your own risk" or something similar.

Background: We're at a point where the kernel should be in principal ready to be able to resume, but we don't yet know how users' modems behave on SMS/calls (some modems have wakeup enabled, some don't) and don't have any policy yet to handle apps that are connected to the internet. This situation might not change for a while so it would be worth adding such a warning.