redundant feedback for `I u'

redundant feedback for `I u'

     When 3.4.0 added the shop price to inventory display of unpaid items,
it resulted in showing that price twice if you used the `I u' command while
carrying just one unpaid object.

k - a potion of object detection (unpaid, 150 zorkmids)    150 zorkmids

With two or more unpaid objects it uses a menu style display and explicitly
suppresses "(unpaid, N zorkmids)" from the inventory formatting.  Do the
same suppression when there's one item.

k - a potion of object detection                     150 zorkmids