toDistanceString
Formats a distance in metres for display, choosing the unit from the magnitude.
An earlier revision consulted ICU's usage("road") so CLDR could pick the unit. It was removed: CLDR's road preferences also impose road rounding, which snaps to the nearest 10 m under 300 m and 50 m above it — so a node 87 m away read "90 m", and the GNSS-accuracy and position-precision labels that share this function are not road distances at all. It also disagreed with the requested system on the locales ICU reports as US but CLDR has no road entry for.