Add a "B" suffix to memory quantities in top(1) output.

Otherwise small quantities look nonsensical.  For instance, when
swapping in a single page we would print "4096 In".

Fix code indentation while here.

MFC after:	1 week
Sponsored by:	The FreeBSD Foundation

usr.bin/top/utils.c

@@ -297,7 +297,8 @@ format_k(int64_t amt)
 
 	ret = retarray[index_];
 	index_ = (index_ + 1) % NUM_STRINGS;
-	humanize_number(ret, 6, amt * 1024, "", HN_AUTOSCALE, HN_NOSPACE);
+	humanize_number(ret, 6, amt * 1024, "", HN_AUTOSCALE, HN_NOSPACE |
+	    HN_B);
 	return (ret);
 }