Remove unused `n` from PQ; add `reflect.is_bit_set`

core/container/priority_queue/priority_queue.odin

@@ -85,7 +85,6 @@ _shift_down :: proc(pq: ^$Q/Priority_Queue($T), i0, n: int) -> bool {
 _shift_up :: proc(pq: ^$Q/Priority_Queue($T), j: int) {
 	j := j
 	queue := pq.queue[:]
-	n := builtin.len(queue)
 	for 0 <= j {
 		i := (j-1)/2
 		if i == j || !pq.less(queue[j], queue[i]) {

core/reflect/types.odin

@@ -302,6 +302,11 @@ is_dynamic_map :: proc(info: ^Type_Info) -> bool {
 	_, ok := type_info_base(info).variant.(Type_Info_Map)
 	return ok
 }
+is_bit_set :: proc(info: ^Type_Info) -> bool {
+	if info == nil { return false }
+	_, ok := type_info_base(info).variant.(Type_Info_Bit_Set)
+	return ok
+}
 is_slice :: proc(info: ^Type_Info) -> bool {
 	if info == nil { return false }
 	_, ok := type_info_base(info).variant.(Type_Info_Slice)