Menu Item Extras - create short description

Tagged as DrupalCon Lille 23 and Novice

We, the mentoring team, are triaging issues for first time contributors at DrupalCon Lille and I think this is a good issue for the contribution day.
We are reserving this issue so please don't work on this issue if you are not at DrupalCon Lille. You can continue the work when the event is over.

I'd suggest to describe this in a simpler way:

"Adds flexibility to menu links by enabling custom fields."

Short and informative! Sounds good to me.