refactor: Enhance docs, code, add tests in Huffman

[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

❌ Patch coverage is 63.76812% with 25 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.83%. Comparing base (a0b6c52) to head (f7f328c).

Files with missing lines	Patch %	Lines
...rc/main/java/com/thealgorithms/others/Huffman.java	63.76%	20 Missing and 5 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #6646      +/-   ##
============================================
+ Coverage     75.74%   75.83%   +0.09%     
- Complexity     5765     5779      +14     
============================================
  Files           701      701              
  Lines         19757    19790      +33     
  Branches       3831     3843      +12     
============================================
+ Hits          14964    15007      +43     
+ Misses         4214     4199      -15     
- Partials        579      584       +5     

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