U393 - jousting puddings into a polymorph trap caused 2 identical new monsters

Because hmon_hitmon caches the monster data type, it needs to update this
whenever the monster might polymorph.  It already did this for potions, but
not for jousting.  There are other more complex ways this could be addressed.

doc/fixes34.2

@@ -91,6 +91,8 @@ hostile monsters who follow you between levels won't do so if they're fleeing
 options for font_size for map, menu, message, status, and text all had the 
 	same description of "the size of the map font" in options.c
 when dismounting by choice and unimpaired, try not to land in a known trap
+when jousting a pudding into a polymorh trap, it was possible to end up
+	with two of the new type of monster
 
 
 Platform- and/or Interface-Specific Fixes

src/uhitm.c

@@ -970,6 +970,7 @@ int thrown;
 	    /* avoid migrating a dead monster */
 	    if (mon->mhp > tmp) {
 		mhurtle(mon, u.dx, u.dy, 1);
+		mdat = mon->data; /* in case of a polymorph trap */
 		if (DEADMONSTER(mon)) already_killed = TRUE;
 	    }
 	    hittxt = TRUE;
@@ -986,6 +987,7 @@ int thrown;
 		/* avoid migrating a dead monster */
 		if (mon->mhp > tmp) {
 		    mhurtle(mon, u.dx, u.dy, 1);
+		    mdat = mon->data; /* in case of a polymorph trap */
 		    if (DEADMONSTER(mon)) already_killed = TRUE;
 		}
 		hittxt = TRUE;