[`getAll`] Add an option(?) so that formatted coords can be returned

[DmitrySharabin]

This idea initially came from the need to show coords in a color swatch formatted as they are in the parsed color. Something like this:

@LeaVerou pointed out that, unfortunately, there is no way to do it now, but it might be a good feature of getAll().

So, I'm filing this issue to request this feature. 🙃

[LeaVerou]

Low hanging fruit would be to add precision, we could also add type which would serialize to <angle> or <percentage>.