By default, `typeset` defines variables locally unless in the main scope.
This is specially bad when using `omz plugin load`, which happens inside
a function, so the declared variables don't continue being defined when
the function finishes and the main scope reappears.

Fixes #10562

Fixes #10560

Also cleaned up the code a bit

Fixes #10561

Closes #10548

Fixes #10549

`restart` is a unit-related command, not power-related, so it should appear as `sc-restart=sudo systemctl restart` and `scu-restart=systemctl --user restart`

Closes #9989