add is_power_of_two with doctests

[MeloveGupta]

Describe your change:

What I changed
Added algorithms/math/power_of_two.py implementing is_power_of_two with doctests.

Why
Small algorithm addition with tests — good first contribution to ease review.

Notes

• Filename in lowercase.
• Includes doctests to follow repository testing pattern.

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

[MeloveGupta]

Hi @mindaugl, Could you please add the hacktoberfest-accepted label (or merge when convenient)? Hacktoberfest only counts PRs that are merged by maintainers or explicitly labeled as accepted. Thank you!

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On Tue, 21 Oct 2025 at 23:37, Mindaugas ***@***.***> wrote: ***@***.**** approved this pull request. — Reply to this email directly, view it on GitHub <#13648 (review)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/A4SCMGKR7HQVD4LWLYV7AND3YZY7BAVCNFSM6AAAAACJZGYCU2VHI2DSMVQWIX3LMV43YUDVNRWFEZLROVSXG5CSMV3GSZLXHMZTGNRSGA3TAOBYGY> . You are receiving this because you authored the thread.Message ID: ***@***.***>