| alias? | (string | AliasConfig)[] | Provide an array of aliases for the option.
Each entry may be a string, or an object with `{ name, hidden }`. When
`hidden: true` is set, the alias still works when parsing arguments but
will not be displayed in help output or generated documentation. |
| choices? | TChoices | () => TChoices | Provide an array of choices for the option. Values not in the array will throw an error. |
| coerce? | (value: T) => TCoerce | Provide a function to coerce the value of the option. |
| default? | Default<NoInfer<T>> | Provide a default value for the option.
If the default value is a tuple, the first value will be used as the default value, and the second value will be used as the description. |
| deprecated? | string | If set, the option will be marked as deprecated, with the provided message. This will not effect runtime behavior,
but will be displayed in help output and generated docs. |
| description? | string | Provide a description for the option. |
| env? | string | boolean | { key?: string; populate?: boolean; prefix?: boolean; reflect?: boolean } | If set, the option will be populated from the environment variable `${env}_${optionName}`.
If set to true, the environment variable will be `${optionName}`.
If explicitly set to false, environment variable population will be disabled for this option. |
| group? | string | Can be set to group options in help output and generated docs. |
| hidden? | boolean | If true, the option will not be displayed in help output or generated docs. |
| positional? | boolean | If set to true, the option will be treated as a positional argument. |
| required? | boolean | If true, the option is required. |
| validate? | (value: TCoerce) => boolean | string | Provide a function to validate the value of the option. |
