bomb: Don't list bombable commodities on invalid selection
comm_bomb() first lists commodities that can be bombed and are
present, then prompts for the one to bomb. If the player selects a
bomb-proof one, it rejects it, lists the bombable ones, and prompts
again. This can only happen when option SUPER_BARS is enabled, and
the player selects bars. Looks like this:
Bomb what? (ship, plane, land unit, efficiency, commodities) c
some civilians
some military
commodity to bomb? b
You can't bomb bars of gold!
Bombable: civilians, military, shells, guns, petrol, iron ore, dust (gold), food, oil, light products, heavy products, uncompensated workers, radioactive materials
commodity to bomb?
The list is of marginal value. It was more useful back when
comm_bomb() didn't list commodities before prompting (BSD Empire 1.1).
It's also illegible. Drop it.
Signed-off-by: Markus Armbruster <armbru@pond.sub.org>