buglist entry: hobbits and elven mithril armour

<Someone> wrote: "Also, hobbits can't wear armour,
at least, you can't wear armour when polymorphed into a hobbit, even
though hobbits do tend to be carrying elven mithril-coats.
It's tempting to suggest adding an explicit exception in
sliparm() for elven mithril just to keep the Tolkienness."

- added a general routine for adding race-based /object
combination exceptions.
- hobbits can wear elven mithril-coats

src/do_wear.c

@@ -1177,7 +1177,8 @@ boolean noisy;
 	    is_suit(otmp) ? c_suit : 0;
     if (which && cantweararm(youmonst.data) &&
 	    /* same exception for cloaks as used in m_dowear() */
-	    (which != c_cloak || youmonst.data->msize != MZ_SMALL)) {
+	    (which != c_cloak || youmonst.data->msize != MZ_SMALL) &&
+	    (racial_exception(&youmonst, otmp) < 1)) {
 	if (noisy) pline_The("%s will not fit on your body.", which);
 	return 0;
     } else if (otmp->owornmask & W_ARMOR) {