Describe your change:

This PR adds a comprehensive Splay Tree implementation to the binary tree data structures collection.

Features:

• Self-balancing binary search tree with splay operations
• O(log n) amortized time complexity for all operations
• Generic implementation supporting any comparable type
• Complete set of operations: insert, delete, search, find_min, find_max
• Comprehensive error handling with proper exception raising
• 65 passing doctests covering normal and edge cases
• Educational implementation with detailed documentation

Algorithm Details:

• Time Complexity: O(log n) amortized for all operations
• Space Complexity: O(n)
• Educational Value: Demonstrates self-adjusting trees, amortized analysis, and tree rotations
• Source: https://en.wikipedia.org/wiki/Splay_tree

File Location: data_structures/binary_tree/splay_tree.py

• 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?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".