📝 README: Remove now done TODO items

Author: zeenix

README.md

@@ -85,8 +85,6 @@ MIT
 
 ## TODO
 
-* Update to heapless' next release when it's out and remove `vec::IntoIter` manual implementation
-* `Box<T>`
 * `Arc<T>`
 * `Deque<T>`
 * `Map<K, V>`