- Enforce that an option declaration has a "defaultText" if and only if the
type of the option derives from "package", "packageSet" or "nixpkgsConfig"
and if a "default" attribute is defined.
- Enforce that the value of the "example" attribute is wrapped with "literalExample"
if the type of the option derives from "package", "packageSet" or "nixpkgsConfig".
- Warn if a "defaultText" is defined in an option declaration if the type of
the option does not derive from "package", "packageSet" or "nixpkgsConfig".
- Warn if no "type" is defined in an option declaration.
