fix #K4142 - camera flash vs mimic

When a camera flash hit a mimic which was posing as something, the
feedback mentioned the mimic but didn't bring it out of hiding.

Change to make light pass over a mimic impersonating an object but
unhide one impersonating furniture.  Ones impersonating some other
monster are woken up but wakeup doesn't force it back to mimic shape.

Trying to get the messages right brought on more code changes than
antipated.  I changed one of the arguments to mhidden_description()
so had to change its callers; fortunately there aren't very many.

doc/fixes3-7-0.txt

@@ -1,4 +1,4 @@
-NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.1416 $ $NHDT-Date: 1712453344 2024/04/07 01:29:04 $
+NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.1427 $ $NHDT-Date: 1713334798 2024/04/17 06:19:58 $
 
 General Fixes and Modified Features
 -----------------------------------
@@ -1929,6 +1929,8 @@ if a tame or peaceful monster was trapped and blind hero hadn't seen the trap
 	yet, attempting to swap places would report "You stop.  <Mon> can't
 	move out of that trap." and if the 'tips' option was On, #untrap would
 	be suggested; but #untrap would fail due "you know of no traps there"
+camera flash hitting a hidden mimic mentioned it as being a mimic but didn't
+	bring it out of hiding
 
 
 Fixes to 3.7.0-x Platform and/or Interface Problems Exposed Via git Repository