precision=day should return "today" instead of "now"

[jyasskin]

https://jsfiddle.net/oabcw7mz/ has an example of trying to render (now - 23 hours) with a precision of days, which should show "today" but actually shows "now".

I think the fix will involve making getRelativeTimeUnit

relative-time-element/src/duration.ts

Lines 206 to 218 in a0483ce

	export function getRelativeTimeUnit(
	duration: Duration,
	opts?: Partial<RoundingOpts>,
	): [number, Intl.RelativeTimeFormatUnit] {
	const rounded = roundToSingleUnit(duration, opts)
	if (rounded.blank) return [0, 'second']
	for (const unit of unitNames) {
	if (unit === 'millisecond') continue
	const val = rounded[`${unit}s` as keyof Duration] as number
	if (val) return [val, unit]
	}
	return [0, 'second']
	}

return the precision unit for empty durations.

[keithamus]

Sounds like you have a good handle on the problem. Would you like to make a PR?