refactor: Enhance docs, add tests in PerlinNoise

[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 92.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 76.79%. Comparing base (69d8406) to head (dd0b90d).

Files with missing lines	Patch %	Lines
...ain/java/com/thealgorithms/others/PerlinNoise.java	92.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #6635      +/-   ##
============================================
+ Coverage     76.60%   76.79%   +0.19%     
- Complexity     6026     6047      +21     
============================================
  Files           719      719              
  Lines         20326    20342      +16     
  Branches       3937     3940       +3     
============================================
+ Hits          15571    15622      +51     
+ Misses         4164     4128      -36     
- Partials        591      592       +1     

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[DenizAltunkapan]

Thank you @Hardvan