kilowatt_hour doesn’t get formatted correctly

Minimal reproducible example: ```python ureg = UnitRegistry(locale="fr_FR") ureg.formatter.format_babel(ureg.Unit("kWh")) ``` Result: ``` kilowatt_hour ``` Expected result: ``` kilowatt-heure ``` It seems to come from `compound_unit_helpers.localize_unit_name`, which should probably look up the name `kilowatt_hour` in `babel_names._babel_units`, but doesn’t, (and `_find_unit_pattern` just returns None…)