git issue #994 - killed by a touch of death

Issue reported by vultur-cadens:  cause of death reason for touch
of death and death due to loss of strength only showed the cause,
not the monster spellcaster who was responsible.

This changes
|Killed by a touch of death.
to
|Killed by the touch of death inflicted by the Wizard of Yendor.
and
|Killed by terminal fraility.
to
|Killed by strength loss inflicted by a chameleon imitating an arch-lich.
(The 'imitating' part doesn't fit on the tombstone but will be present
in logfile/xlogfile.)

Noticed while implemented this:  touch of death was modifying u.uhpmax
and basing death vs damage on that even when hero was polymorphed.
It now rehumanizes the hero in that situation.

Closes #994

src/polyself.c

@@ -1254,6 +1254,10 @@ rehumanize(void)
             gk.killer.format = NO_KILLER_PREFIX;
             Strcpy(gk.killer.name, "killed while stuck in creature form");
             done(DIED);
+            /* can get to here if declining to die in explore or wizard
+               mode; since we're wearing an amulet of unchanging we can't
+               be wearing an amulet of life-saving */
+            return; /* don't rehumanize after all */
         } else if (uamul && uamul->otyp == AMULET_OF_UNCHANGING) {
             Your("%s %s!", simpleonames(uamul), otense(uamul, "fail"));
             uamul->dknown = 1;
@@ -1274,7 +1278,8 @@ rehumanize(void)
         /* can only happen if some bit of code reduces u.uhp
            instead of u.mh while poly'd */
         Your("old form was not healthy enough to survive.");
-        Sprintf(gk.killer.name, "reverting to unhealthy %s form", gu.urace.adj);
+        Sprintf(gk.killer.name, "reverting to unhealthy %s form",
+                gu.urace.adj);
         gk.killer.format = KILLED_BY;
         done(DIED);
     }