github issue #1262 - #terrain vs gas regions

Issue reported by elunna:  none of the display choices for #terrain
offered a way to show the terrain beneath temporary gas/cloud
regions (except "full map" in wizard mode or explore mode).  That
prevented the command from being used to find stairs and portals
which had been mapped before becoming covered up.

Adding extra menu choices to deal with visible regions would result
in #terrain becoming a mess.  Instead, treat regions as if they were
traps.  Picking a choice that includes traps will show region spots
which are in view as cloud or poison cloud, picking one that excludes
traps will show the underlying terrain.  Region spots which aren't
within view are handled the same as before:  whatever the hero
remembers at their location gets displayed.

The default menu choice excludes traps so will display stairs that are
covered by gas cloud regions, but not portals, same as when no regions
are present.  When showing traps and one is covered by a gas cloud,
the trap will be shown rather than the gas cloud, making it possible
to see known portals.

At the moment the new "#terrain handles regions like traps" feature
hasn't been documented anywhere.  That might get rectified someday.

I'm not sure whether trap detection ought to also detect regions now.
This doesn't attempt to tackle that and I think that I'll pretend
that the idea never occurred to me.

'parnoid_confirm:traps' definitely ought to prompt for confirmation
when entering a visible harmful region.  This doesn't add that.

Bonus fix:  it's possible for a visible region to cover up a not yet
explored location.  Searching next to such a spot wasn't changing the
spot to be marked as explored (unless hero was blind).  Now it will.

Fixes #1262

doc/fixes3-7-0.txt

@@ -1,4 +1,4 @@
-NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.1455 $ $NHDT-Date: 1720895738 2024/07/13 18:35:38 $
+NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.1457 $ $NHDT-Date: 1721684298 2024/07/22 21:38:18 $
 
 General Fixes and Modified Features
 -----------------------------------
@@ -1451,6 +1451,9 @@ when setting an option interactively [via O or 3.7's mO], if the particular
 	list of option[:value] rather than just the new value of that option
 when there was a trap on a no-dig level, the floor beneath it was always
 	"too hard to dig into", making it impossible to remove the trap
+the #terrain command didn't know how to cope with visible gas/cloud regions;
+	treat as traps as far as player choice of whether to show or hide;
+	if/when a spot contains both region and trap, show the trap
 
 
 Fixes to 3.7.0-x General Problems Exposed Via git Repository