power: Label the PENDING_CHARGING state as Fully Charged
The pending-charge state means AC power is on but the battery is not
being charged because its charge is above a certain threshold, to avoid
short charging cycles and prolong the battery's life. In fact,
/sys/class/power_supply/BAT1/status
literally says "Not charging".
From the user's perspective this is equivalent to the situation where the battery is fully charged. On certain laptops like the Lenovo Yoga 900 the battery management hardware will even report (through ACPI) the status as fully-charged instead of pending-charged under this scenario.
This commit sets the details string for the pending-charge state to "Fully Charged".
Closes: #249 (closed)