3.7: automatic annotation for vibrating square

Add "Gateway to Moloch's Sanctum" to the vibrating square level if you
step on the square or detect/magic map it as a pseudo-trap, an extra
hint for players who manage to get that far but then don't know what
to do next.  (I think I may also add a randomly placed floor engraving
along the lines of "For a good time, consult the Oracle of Delphi."
as a gag variant of "For a good time, call <name> at <phone number>."
Not very thematic for Gehennom but could conceivably nudge someone in
the right direction.  But it could give away the level for experienced
players who haven't located the vibrating square yet.)

The annotation sticks until the one for "Moloch's Sanctum" gets added.
That happens when the temple on the sanctum level is entered or the
altar there has become mapped (in view or via magic mapping).

Could break existing 3.7.0- save files (but probably won't, since
at least two bits were available unless using an ancient 'Bitfield()
allocates whole bytes' configuration).  That's the reason I didn't
put this into 3.6.2+.

doc/fixes37.0

@@ -3,6 +3,10 @@ $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.8 $ $NHDT-Date: 1557663358 2019/05
 General Fixes and Modified Features
 -----------------------------------
 fix compile when DLB isn't defined
+hero polymorphed into a vampire can use #monster to shape-shift rather than
+	just do a one-shot polymorph into bat/cloud/wolf and shifted vampire
+	hero can use #monster again to take on another form (randomly chosen
+	among the shiftable shapes and true vampire form)
 
 
 Fixes to Pre-3.7.0 Problems that Were Exposed Via git Repository
@@ -17,6 +21,9 @@ General New Features
 --------------------
 if a killer bee encounters a lump of royal jelly and there is no queen bee on
 	the level, the bee will eat the jelly and become a new queen
+automatic annotation "gateway to Moloch's Sanctum" for vibrating square level
+	once that square's location becomes known (found or magic mapped);
+	goes away once sanctum temple is found (entered or high altar mapped)
 
 
 Platform- and/or Interface-Specific New Features