adig: fix NAPTR parsing

I ran across a small "issue" in your adig example.

It is simply the last part of the NAPTR record, the replacement element,
which is not a string, as currently handled in adig, but a domain name.

adig.c

@@ -744,7 +744,7 @@ static const unsigned char *display_rr(const unsigned char *aptr,
       ares_free_string(name.as_char);
       p += len;
 
-      status = ares_expand_string(p, abuf, alen, &name.as_uchar, &len);
+      status = ares_expand_name(p, abuf, alen, &name.as_char, &len);
       if (status != ARES_SUCCESS)
         return NULL;
       printf("\t\t\t\t\t\t%s", name.as_char);