fix #H1554, #H1736, github issue #240 - silver )

Fixes #240

Monster versus monster (melee and throwing) didn't handle shades
(need silver or blessed weapon to take damage) or silver feedback
(extra info when silver-haters are hit).

I did a lot of test, revise, re-test but didn't always re-test
everything that had previously been tested, so bugs that I thought
were quashed might have crept in.

Now if a missile weapon "passes harmlessly through the shade" it
will continue on and maybe hit something else.  (Regular misses
still stop at the missed target.)

A couple of minor ball&chain changes accidentally got included.

doc/fixes36.3

@@ -1,4 +1,4 @@
-$NHDT-Branch: NetHack-3.6 $:$NHDT-Revision: 1.171 $ $NHDT-Date: 1573505739 2019/11/11 20:55:39 $
+$NHDT-Branch: NetHack-3.6 $:$NHDT-Revision: 1.172 $ $NHDT-Date: 1573688684 2019/11/13 23:44:44 $
 
 This fixes36.3 file is here to capture information about updates in the 3.6.x
 lineage following the release of 3.6.2 in May 2019. Please note, however,
@@ -223,6 +223,7 @@ putting on gloves while having slippery fingers transfered slipperiness to
 	losing them in other ways transfered slipperiness to bare fingers
 when a monster reads a scroll of fire to cure sliming, don't access that
 	scroll's memory after it has been used up (bcsign)
+monster vs monster attacks didn't handle shades or silver weapon feedback
 
 
 Fixes to Post-3.6.2 Problems that Were Exposed Via git Repository