Is `date.format.localeFormat` from `l10n_date` already? 

If so, maybe we could make a function like `{[ plural ]}`

`test = {[ dateFormat('date_format_key', dateStart) ]} to {[ dateFormat('date_format_key', dateEnd) ]}

Then dateStart / dateEnd would be dates/Number timestamps - and the `'date_format_key'` would get looked up while localizing