update documentation
only mount /nix, not the whole host-system
Merge branch 'systemd/multi-shell-support' into refs/top-bases/systemd/marc

* systemd/multi-shell-support:
  update documentation
Merge branch 'experimental/minimal-install-archive' into refs/top-bases/systemd/marc

* experimental/minimal-install-archive:
  only mount /nix, not the whole host-system
Merge commit 'refs/top-bases/systemd/marc' into systemd/marc

* commit 'refs/top-bases/systemd/marc':
  only mount /nix, not the whole host-system
  update documentation