vcard: Expand documentation (#249825)

  meta = {

    homepage = "https://gitlab.com/engmark/vcard";

    description = "vCard validator, class and utility functions";

    longDescription = ''

      This program can be used for strict validation and parsing of vCards. It currently supports vCard 3.0 (RFC 2426).

    '';

    license = lib.licenses.agpl3Plus;

    mainProgram = "vcard";

    maintainers = [ lib.maintainers.l0b0 ];

  };

}