Apart from being bad practice, absolute paths may be confusing;
especially the `services.emacs.package` definition in the "Running
Emacs as a service" section. Remove them.
Supersedes: https://github.com/NixOS/nixpkgs/pull/192019
Co-authored-by: Alexander Bantyev <balsoft@balsoft.ru>
these examples were turned into untitle anchors previously because at
the time supporting examples was not deemed necessary or useful. now
that we have them we can restore them though.
