[mypy] check polygon and corrections (#5419)

* Update annotations to Python 3.10 #4052

* Add floats doctest

* Copy list to avoid changing input unpredictably

* Refactor code to make it readable

* updating DIRECTORY.md

* Improve raised ValueErrors and add doctest

* Split doctest in multiples lines

* Change ValueError to Monogons and Digons are not poly

* Correct doctest refering number of sides

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