Change label to checkboxes in menus

[Luciano Montanaro]

I was not aware that checkboxes could need this kind of
disambiguation. Nice to know.
However, I find the checkbox form makes my life easier as a translator
as well as a user, most of the time.

As a translator, I get to translate less messages, and as a user, I
find that the checkmark is a much better clue to what the menu item
does/how it works.

-- 
Luciano Montanaro

Anyone who is capable of getting themselves made President should on
no account be allowed to do the job. -- Douglas Adams