Fix/kth lexicographic permutation

[yaadhuu]

Summary

This pull request improves the clarity and robustness of
kth_lexicographic_permutation without changing the underlying algorithm.

Changes

• Fixed a docstring inconsistency to correctly describe the permutation range
  as 0, 1, 2, ..., n-1.
• Corrected a small typo in a comment.
• Replaced the use of assert with explicit input validation using
  TypeError and ValueError for clearer and more reliable error handling.
• Used pop(index) instead of remove(value) to make element removal
  intent explicit.

Why this change

These changes improve correctness, readability, and alignment with Python
best practices while keeping the algorithm logic and behavior unchanged.
All existing doctests continue to pass.

Scope

This PR is intentionally minimal and limited to a single file.

[algorithms-keeper]

Closing this pull request as invalid

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