This allows for correct highlighting and maybe future automatic formatting. The AST was verified to work with nixfmt only.
pandoc would drop these when converting to docbook, just like it dropped .title block classes.
mkOrder
Add a section on ordering option definitions. Also mention `mkDefault` in the section on `mkOverride`. Clarify the code a bit by renaming `defaultPriority` to `defaultOverridePriority` and introducing `defaultOrderPriority`.
