refactor: Enhance docs, add tests in CircleLinkedList

[Hardvan]

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

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 68.77%. Comparing base (c766c5e) to head (1a6805e).

Files with missing lines	Patch %	Lines
...orithms/datastructures/lists/CircleLinkedList.java	83.33%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #5991   +/-   ##
=========================================
  Coverage     68.76%   68.77%           
- Complexity     4633     4634    +1     
=========================================
  Files           620      620           
  Lines         17107    17106    -1     
  Branches       3300     3300           
=========================================
+ Hits          11764    11765    +1     
+ Misses         4892     4891    -1     
+ Partials        451      450    -1     

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