Added logic gates xor and xnor in Boolean Algebra

[KuldeepBorkar]

Describe your change:

• [x] Add an algorithm?
• [ ] Fix a bug or typo in an existing algorithm?
• [ ] Documentation change?

Checklist:

• [x] I have read CONTRIBUTING.md.
• [x] This pull request is all my own work -- I have not plagiarized.
• [x] I know that pull requests will not be merged if they fail the automated tests.
• [x] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• [x] All new Python files are placed inside an existing directory.
• [x] All filenames are in all lowercase characters with no spaces or dashes.
• [x] All functions and variable names follow Python naming conventions.
• [x] All function parameters and return values are annotated with Python type hints.
• [x] All functions have doctests that pass the automated testing.
• [x] All new algorithms have a URL in its comments that points to Wikipedia or other similar explanation.
• [x] If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[KuldeepBorkar]

@CaedenPH I think I have made a mistake while updating the repo and merging conflicts and somehow that other change of Binary tree came ; ( I am trying to fix it but confused what should I do can you please help??? Update: I used git revert HEAD to revert the unnecessary changes, I think now its okay : )

[CaedenPH]

@cclauss This has already been implemented #7596

[KuldeepBorkar]

@CaedenPH Oh! I think I actually added this earlier 15 days ago but didn't receive any reviews and now it is implemented 😿