Add a `booleanish` option about meow

[sindresorhus]

I like the idea in general and I've had the same problem previously too, but not entirely sold on this exact implementation. Why not just let the user specify an option as both string and boolean in the minimist options and handle it accordingly? Or maybe introduce a new type in the minimist options called any (I prefer it over booleanish):

const cli = meow('help', {
  any: ['debug']
});

parse seems more general and could be added independently of this change, as it could be useful for the string type too.

false: What gets returned if no flag appears (or --no-debug is used).

No flag and --no-debug are different. No flag returns undefined while --no-debug returns false. This distinction is usually not important, but can be.

// @kevva @SamVerschueren

[Mouvedia]

Why not just let the user specify an option as both string and boolean in the minimist options and handle it accordingly?

Is this supported?