refactor: Enhance docs, add more tests in `SwapAdjacentBits`

[Hardvan]

• [x] I have read CONTRIBUTING.md.
• [x] This pull request is all my own work -- I have not plagiarized it.
• [x] All filenames are in PascalCase.
• [x] All functions and variable names follow Java naming conventions.
• [x] All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• [x] All new code is formatted with clang-format -i --style=file path/to/your/file.java

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 72.97%. Comparing base (b31bc86) to head (f534bd3).

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #5861   +/-   ##
=========================================
  Coverage     72.97%   72.97%           
  Complexity     5029     5029           
=========================================
  Files           655      655           
  Lines         17588    17588           
  Branches       3387     3387           
=========================================
  Hits          12834    12834           
  Misses         4262     4262           
  Partials        492      492           

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