rb: fix rb.Node.getLast() that never worked
rb: fix rb.Node.getLast() that never worked

andrewrk/zig,zig-lang/zig,andrewrk/zig,raulgrell/zig,raulgrell/zig,raulgrell/zig,raulgrell/zig,raulgrell/zig,zig-lang/zig,zig-lang/zig