Correct Treap split docstring to reflect actual working, Fixes: #7854

[utpalsavliya]

Corrected the split docstring to reflect the working of the function, i.e., elements equal to the split value will be contained by left subtree, which before correction the docstring stated to be contained in the right subtree.

Describe your change:

Implemented the suggestion by @vbvg2008 for issue #7854 to correct the docstring. Didn't choose to modify the code as stated in the latter part of suggestion as I found couple of resources online which kept the elements equal to the key in left subtree, supporting the former part of the suggestion.
Links to resources -
https://cp-algorithms.com/data_structures/treap.html#implicit-treaps
https://medium.com/carpanese/a-visual-introduction-to-treap-data-structure-part-1-6196d6cc12ee

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Documentation change?

Checklist:

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