instead of as fake bear traps
Use the new traps and their tiles when confused gold detection finds
trapped doors and trapped chests. (Large boxes can be trapped too;
they use the trapped chest trap and corresponding tile rather than
have their own.)
Usually these pseudo-traps go away when as soon as they are within
line of sight. (While testing, I noticed that seeing a trapped door
from outside its room rather than inside didn't behave that way.
The door was created by wizard mode wishing; I don't know whether
that was a factor.)
I also discovered that secret doors weren't being handled correctly.
They can't be trapped because of their use of both the doormask and
wall_info overlays of levl[][].flags, but I had a secret door be
falsely displayed as a trap. This fixes that.
We should have obj->tknown and rm->D_TRAPKNOWN so that the hero won't
forget about these traps after declining to attempt to untrap them.
But that's more work than I care to tackle.
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