fix github issue #894 - guardian nagas can't grab

Issue reported by eakaye:  for a 'hugs' attack to succeed, the
monster must have at least three attacks and the two preceding the
hug attack need to both hit.  Guardian nagas had three attacks but
the first was melee 'bite' and the second was ranged 'spit'.  Those
are mutually exclusive, so they would never both hit and nagas never
grabbed their prey.

Make the spit attack be first, the bite attack be second, insert a
touch attack for 0 damage third, and make the hug be fourth.  Also,
change their hug damage type from 'phys' to 'wrap'.  The first and
2nd+3rd+4th are still mutually exclusive.

The resulting message feedback left something to be desired and has
been tweaked.

The difficulty-level formula used by deprecated 'makedefs -m' now
generates 17 rather than 16 for guardian naga so I changed revised
monster to match.  They are definitely more difficult now that their
constriction attack has a chance to hit.

Fixes #894

doc/fixes3-7-0.txt

@@ -1,4 +1,4 @@
-HDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.1049 $ $NHDT-Date: 1664966382 2022/10/05 10:39:42 $
+HDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.1051 $ $NHDT-Date: 1665130022 2022/10/07 08:07:02 $
 
 General Fixes and Modified Features
 -----------------------------------
@@ -1043,6 +1043,8 @@ hero with exceptional strength (18/01..18/100) retained that when polymorphed
 	into any monster lacking the strongmonst attribute
 give hero poly'd into a giant 19 strength instead of 18/100
 wait for a response after displaying wishing help; affects X11
+guardian nagas' constriction attack could never hit because the two preceding
+	attacks must both hit and those were mutually exclusive: bite and spit
 
 
 Fixes to 3.7.0-x Problems that Were Exposed Via git Repository