Feature request: add support for only the year instead of the full date

[cdwijs]

I would like to specify I've worked for a company from 2004 - 2006, without specifying the exact date. This doesn't work yet.
When I enter dd/mm/yyyy, the date is invisible. This is good.
When I enter 03/09/2008, the date is rendered as "Mar, 2013". This is good.
When I enter dd/mm/2021, the date is invisible. It would be nice if it was rendered as "2021"