B15004 - Master Assassin's attack

hitmu was trying, and failing, to re-implement parts of x_monnam().  Changed
it to use Monnam(), which produces more detailed messages than before in
some cases, but seems better since its messages are now more consistent
with hitmsg() and prints "The" in this specific case.

src/mhitu.c

@@ -989,10 +989,7 @@ dopois:
 		hitmsg(mtmp, mattk);
 		if (uncancelled && !rn2(8)) {
 		    Sprintf(buf, "%s %s",
-				!canspotmon(mtmp) ? "Its" :
-				Hallucination ? s_suffix(rndmonnam()) :
-				                s_suffix(mdat->mname),
-				mpoisons_subj(mtmp, mattk));
+			    s_suffix(Monnam(mtmp)), mpoisons_subj(mtmp, mattk));
 		    poisoned(buf, ptmp, mdat->mname, 30);
 		}
 		break;