* added radix tree to data structures
* added doctests
* solved flake8
* added type hints
* added description for delete function
* Update data_structures/trie/radix_tree.py
* Update radix_tree.py
* Update radix_tree.py
* Update radix_tree.py
Co-authored-by: Alex de la Cruz <alex@Alexs-MacBook-Air.local>
Co-authored-by: Christian Clauss <cclauss@me.com>