#23

treefmt: update config and add formatters

GitHubActions: change nix to lix and update cache backend

Add TLSA+SSHFP record types

document a classical nix setup

Add trailing dot to cnames

fix: txt records for too long values

clean up lib.mdDoc, update flake.lock, introduce treefmt-nix/nixfmt, cleanup patches, use specialArgs where sensible.

simplify condition

fix typos