Any time estimates we can come up with are notoriously unreliable;
even on devices that report correct (dis)charging rates, any change
in workload, screen brightness etc. can throw our estimate off by
a huge amount. This is further compounded by bad firmware and battery
firmware which reports inaccurate data as neither Windows nor Android do
not use that data.
So instead, limit ourselves to only showing the current percentage
and leave its interpretation to the user.
As an added bonus, we end up with shorter strings that are less likely
to cause problems with ellipsization when translated.
https://bugzilla.gnome.org/show_bug.cgi?id=708472
6c08799c7b