Extend the package override FAQ with flake examples for modules that expose a package option and modules that require an overlay.
Clarify that Home Manager nixpkgs.overlays only applies to standalone configurations or system-module configurations that do not enable home-manager.useGlobalPkgs.
For useGlobalPkgs setups, direct users to put overlays in the system configuration and pass any flake-provided package sets through nixosSystem or darwinSystem specialArgs.
Austin Horstman
938311a3bd