Fix doctest bug in bubble_sort_recursive - incorrect function call

[MathewAddala]

Fixed bug in bubble_sort_recursive docstring where the doctest was calling bubble_sort_iterative([]) instead of bubble_sort_recursive([]). This was a copy-paste error that would cause the doctest to pass even if bubble_sort_recursive had issues with empty lists.

Change:

• Line 71: Changed '>>> bubble_sort_iterative([])' to '>>> bubble_sort_recursive([])'

This ensures the doctest properly validates the recursive implementation.

Describe your change:

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
• Documentation change?

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