github PR #259 - paranoid_confirmation:trap

Fairly old pull request from copperwater:  add new paranoid_confirm
setting 'trap'.

The old commit suffered from bit rot and merging needed too much
fixing up despite there not being many bands of change in the commit's
diffs.  I ultimately redid it from scratch, although the two biggest
chunks of code started with copy+paste of the pull request's commit.

It operates like paranoid:pray.  Setting paranoid:trap adds a new
"Really step into <trap>?" y/n prompt when attempting to move
into/onto a known trap, even if an object covers it on the map.
Setting both 'paranoid:Confirm trap' turns that into a yes/no prompt.
(Adding 'Confirm' affects other paranoid confirmations; in addition
to requiring yes<return> rather than just y to accept, it also forces
no<return> to reject.)

However, moving into a known trap that is considered to be harmless
behaves as if no trap was present.  Some of the trap classification
might be out of date; several types of traps have undergone changes
since implementation of the original pull request, notably anti-magic
field.  When the hero is hallucinating, all known traps are considered
harmful since the map no longer reliably describes them.

Preceding a movement command with the 'm' prefix also behaves as if
no trap was present, bypassing confirmation for that move, similar to
how paranoid:swim currently behaves.  Being stunned or confused also
behaves as if no trap was present, taking priority over hallucination.

This updates the documentation.

Supersedes #259
Closes #259

include/extern.h

@@ -2913,6 +2913,7 @@ extern struct monst *animate_statue(struct obj *, coordxy, coordxy,
                                     int, int *);
 extern struct monst *activate_statue_trap(struct trap *, coordxy, coordxy,
                                           boolean);
+extern int immune_to_trap(struct monst *, unsigned);
 extern void set_utrap(unsigned, unsigned);
 extern void reset_utrap(boolean);
 extern void dotrap(struct trap *, unsigned);