I've noticed quite a few pull requests are being submitted with formats
such as feat(abc): or target: at the start of the message.
It will be helpful to have a specific format for this to keep things
consistent.
The Tinted Theming repository is now packaged in Nixpkgs, so we
don't need to list other ways to obtain it.
Also simplified the links to the preview as `$XDG_CONFIG_HOME`
is rarely modified.
