refactor: Enhance docs, remove main, add tests in AnytoAny

[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 94.44444% with 1 line in your changes missing coverage. Please review.

Project coverage is 70.76%. Comparing base (4e46002) to head (caf5d8a).

Files with missing lines	Patch %	Lines
...n/java/com/thealgorithms/conversions/AnytoAny.java	94.44%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5916      +/-   ##
============================================
+ Coverage     70.65%   70.76%   +0.11%     
- Complexity     4849     4856       +7     
============================================
  Files           649      649              
  Lines         17525    17524       -1     
  Branches       3376     3376              
============================================
+ Hits          12382    12401      +19     
+ Misses         4679     4659      -20     
  Partials        464      464              

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