free render group arena in freeRenderState

src/main.cpp

@@ -170,6 +170,7 @@ freeRenderState(RenderState*& rs)
 {
 	if (rs) {
 		arenaFree(rs->assets.arena);
+		arenaFree(rs->rg_arena);
 		utilSafeFree(rs->handles);
 		utilSafeFree(rs);
 		rs = nullptr;