* Since 0d957142b6 the manual doesn't
build since `<name>` is interpreted by docbook as (unmatched) XML-tag.
I decided to use `<xref linkend` as this provides proper linking to
the referenced option.
* Also, if the module is included on a machine where `sops` isn't used,
but `documentation.nixos.includeAllModules = true;` is set, the module
wouldn't evaluate because `config.sopsFile` is referenced in a
`default`-tag. This is generally an issue since every change to this
option would trigger a rebuild of the manual anyways.
See also 94fd200305 for that.
When using `documentation.nixos.includeAllModules = true;`, I'd
otherwise have to rebuild the manual on each change since I have my
`defaultSopsFile` in a git-repo with all my other configs.