config/power-management: mention polkit at elogind

[motorto]

Refer that elogind might depend on polkit for some use cases. (poweroff/reboot).

https://github.com/void-linux/void-packages/pull/38347

[classabbyamp]

commit message should be config/power-management: ... i think

[motorto]

It doesn't seem to be the problem to be honest don't know what I am doing wrong, the ./check script doesn't detect nothing wrong.

[classabbyamp]

run vmdfmt -w src/config/power-management.md, it'll reflow the text