Document hash() limitations in BucketSort; add tests showing distribution behavior

[Leogricci]

Relates to #6503
distribution behavior

Context
Documents the behavior and limitations of hash() in BucketSort. The current logic treats compareTo as if it returned a numeric distance. For numerics, compareTo yields only -1/0/1 (order), and for non-numeric types (e.g., String) the magnitude reflects lexicographic code-point differences rather than proportional spacing. Sorting remains correct due to per-bucket sorting and concatenation, but the resulting bucket distribution is not a meaningful proportional mapping.

Changes

• Expanded Javadoc on hash() explaining limitations and the degenerate min == max case.
• Added BucketSortHashBehaviorTest to demonstrate:
  • All equal values collapse to bucket 0.
  • Numeric arrays map mostly to two buckets (because compareTo is sign-only).
  • Strings distribute by lexicographic differences (arbitrary/uneven spacing).

Observed output (examples)
All-equal case -> bucket index: 0
Value 10 -> bucket 0
Value 20 -> bucket 3
Value 30 -> bucket 3
Value 40 -> bucket 3
Value "apple" -> bucket 0
Value "banana" -> bucket 1
Value "carrot" -> bucket 3

Notes
No algorithm/signature change; documentation + tests only (for learners).

• 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 75.11%. Comparing base (79dc0b4) to head (635fcdb).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #6511      +/-   ##
============================================
+ Coverage     75.10%   75.11%   +0.01%     
  Complexity     5571     5571              
============================================
  Files           685      685              
  Lines         19307    19307              
  Branches       3732     3732              
============================================
+ Hits          14500    14502       +2     
+ Misses         4245     4244       -1     
+ Partials        562      561       -1     

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[Leogricci]

Took a while to get the clang-format right but it should be good now.

[DenizAltunkapan]

Is there any reason why you didn't put your Tests in the exististing BucketSortTest ? @Leogricci

[Leogricci]

Since the issue only related to the particular case of the hash function i thought it might be better to create another test class, but I realize now it just makes it harder to find. Sorry for the inconvenience, I will modify it now.

[DenizAltunkapan]

@Leogricci still working on it?