This should be zero functionality change, just make tooling better.
I'm currently preparing a local 247-rc1 and realized the patches
don't apply properly.

This was introduced in #99621, but
didn't follow the process documented in
pkgs/os-specific/linux/systemd/default.nix, namely, the git am and
git format-patch workflow, which caused
0019-revert-get-rid-of-seat_can_multi_session.patch to not apply with
git am due to missing authorship information.

I did apply this patch manually, and copied authorship information from
4e384dd.

Motivation for this change

Make these lines be accurate again:

# If these need to be regenerated, `git am path/to/00*.patch` them into a
# systemd worktree, rebase to the more recent systemd version, and export the
# patches again via `git format-patch v${version}`.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.