fix(brightness): reading brightness in actual_brightness (#1689)
fix(brightness): reading brightness in actual_brightness (#1689)

As the kernel documentation said:
https://www.kernel.org/doc/Documentation/ABI/stable/sysfs-class-backlight

    This file will also show the brightness level stored in the driver, which may not be the actual brightness (see actual_brightness).

Therefore the brightness value should be read in the actual_brightness file.

Fix #1180
jaagr/lemonbuddy,jaagr/lemonbuddy,jaagr/polybar,jaagr/polybar,jaagr/lemonbuddy,jaagr/polybar