Method erase_from_leaf_node

src/include/cpp-btree/btree.h:2137–2150

template <typename P>
auto btree<P>::erase_from_leaf_node(iterator begin, size_type to_erase)
    -> iterator {
  node_type *node = begin.node;
  assert(node->leaf());
  assert(node->count() > begin.position);
  assert(begin.position + to_erase <= node->count());

  node->remove_values_ignore_children(begin.position, to_erase,
                                      mutable_allocator());

  size_ -= to_erase;

  return rebalance_after_delete(begin);
}

template <typename P>
template <typename K>