Update the documentation to inform users they can create news entries
themselves using `nix run .#create-news-entry` without waiting for
maintainers. This makes the contribution process more self-service
and improves the documentation to match the recently exposed flake
package.
The current way to define a news entry in Home-Manager is error prone
(since you need to type the date manually) and also it is common cause
of conflicts after merges because all entries are defined in the same
file.
This commit fixes this: we can now create individual news entries for
each new entry. A script `create-news-entry.sh` also helps to create it
in the correct format (with the correct filenames and structure).
The `optionsDocBook` function is deprecated in nixpkgs since
nixos-23.11. This commit updates the manual and manpages to
use commonmark formatted documentation instead of the deprecated
docbook format.
