refactor: Enhance docs, add tests in `GenericHashMapUsingArray`

[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

Attention: Patch coverage is 90.90909% with 1 line in your changes missing coverage. Please review.

Project coverage is 73.10%. Comparing base (fd14016) to head (c0b88ef).

Files with missing lines	Patch %	Lines
...ures/hashmap/hashing/GenericHashMapUsingArray.java	90.90%	0 Missing and 1 partial :warning:

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5972      +/-   ##
============================================
+ Coverage     72.97%   73.10%   +0.13%     
- Complexity     5029     5038       +9     
============================================
  Files           655      655              
  Lines         17588    17590       +2     
  Branches       3387     3389       +2     
============================================
+ Hits          12834    12860      +26     
+ Misses         4262     4238      -24     
  Partials        492      492              

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