edit: Print ship and land unit items with field width 5

edit: Print ship and land unit items with field width 5

print_items() uses field widths between 3 and 5.  They go back all the
way to Empire 1, and are fine for the stock game.  Widen the narrower
ones to 5, because a consistent field width looks tidier, and can
avoid misaligned columns with customized ships and land units.

Signed-off-by: Markus Armbruster <armbru@pond.sub.org>