Enhance QuickSort documentation and structure

[prasanth-30011]

Fixes #7143

Updated QuickSort implementation with detailed comments and improved clarity.

• 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

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.62%. Comparing base (2c4bf3c) to head (08a9e4e).
⚠️ Report is 11 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #7149      +/-   ##
============================================
+ Coverage     78.51%   78.62%   +0.10%     
- Complexity     6752     6824      +72     
============================================
  Files           759      765       +6     
  Lines         22402    22599     +197     
  Branches       4400     4443      +43     
============================================
+ Hits          17589    17768     +179     
- Misses         4108     4117       +9     
- Partials        705      714       +9     

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