MAINT Clean up Cython files

[adam2392]

Reference Issues/PRs

Remove unused properties in Cython classes.

What does this implement/fix? Explain your changes.

Move fisher-yates shuffling to an inline function instead of a class method

Any other comments?

[codecov]

Codecov Report

Attention: Patch coverage is 95.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 80.21%. Comparing base (1d970b0) to head (e0dc4a5).
Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
treeple/neighbors.py	77.77%	1 Missing and 1 partial ⚠️
treeple/tree/_classes.py	97.72%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #321      +/-   ##
==========================================
+ Coverage   80.00%   80.21%   +0.20%     
==========================================
  Files          24       24              
  Lines        2221     2254      +33     
  Branches      411      412       +1     
==========================================
+ Hits         1777     1808      +31     
- Misses        312      313       +1     
- Partials      132      133       +1     

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