Update game_of_life.py (#4921)

* Update game_of_life.py

docstring error fix
delete no reason delete next_gen_canvas code(local variable)

* Update cellular_automata/game_of_life.py

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

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Co-authored-by: Tianyi Zheng <tianyizheng02@gmail.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>