Hallu YAFM for stumbling onto an undetected monster

Pokemon reference. Based on an idea by aosdict.

doc/fixes36.2

@@ -144,6 +144,7 @@ status_hilite options which use comparisons may now use <= and >= in
 sortloot option has been enhanced to improve object ordering; primarily,
 	items of undiscovered type come out before items of discovered type
 	within each class or sub-class of objects
+YAFM when stumbling on an undetected monster while hallucinating
 
 
 Code Cleanup and Reorganization

src/uhitm.c

@@ -176,7 +176,10 @@ struct obj *wep; /* uwep for attack(), null for kick_monster() */
         if (!((Blind ? Blind_telepat : Unblind_telepat) || Detect_monsters)) {
             struct obj *obj;
 
-            if (Blind || (is_pool(mtmp->mx, mtmp->my) && !Underwater))
+            if (!Blind && Hallucination)
+                pline("A %s %s appeared!",
+                      mtmp->mtame ? "tame" : "wild", l_monnam(mtmp));
+            else if (Blind || (is_pool(mtmp->mx, mtmp->my) && !Underwater))
                 pline("Wait!  There's a hidden monster there!");
             else if ((obj = level.objects[mtmp->mx][mtmp->my]) != 0)
                 pline("Wait!  There's %s hiding under %s!",