kick/joust monster positioning (trunk only)

From a 7.5 year old news posting (with a reply by Kevin Hugo speaking
on behalf of slash'em...):  when a monster "nimbly jumps to evade" hero's
kick, it can pass through walls and grid bugs can jump off their grid.
Likewise when a joust or staggering blow knocks a monster back, it could
move grid bugs diagonally.  This fixes both cases.

     Offhand I can't think of any other non-standard movement situations
which might need similar handling, but it wouldn't surprise me if there
are some.  Leashed movement is close but I don't think maybe_mnexto helps.

src/dokick.c

@@ -206,7 +206,7 @@ doit:
 		(void) passive(mon, FALSE, 1, AT_KICK, FALSE);
 		return;
 	    } else {
-		mnexto(mon);
+		maybe_mnexto(mon);
 		if(mon->mx != x || mon->my != y) {
 		    if(glyph_is_invisible(levl[x][y].glyph)) {
 			unmap_object(x, y);