Add DocTests to is_palindrome.py (#10081)

* add doctest ut

* test complete

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* format

* ruff update

* cover line 154

* Update data_structures/linked_list/is_palindrome.py

Co-authored-by: Christian Clauss <[email protected]>

* use dataclass

* pre-commit fix

* Fix mypy errors

* use future annotations

---------

Co-authored-by: Harsha Kottapalli <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Christian Clauss <[email protected]>