typing: bind recursive insertion sort to Comparable protocol

[Silverbullets1]

Describe your change

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

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.
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• 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".

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Part of #15234 (the recursive_insertion_sort.py checkbox).

This PR types the recursive insertion sort for any comparable items:

• insert_next was missing its TypeVar bound, so Pyright flagged the < operator on T. Both rec_insertion_sort and insert_next are now [T: Comparable] with the Comparable Protocol (__lt__(self, other: object, /) -> bool), matching the pattern already checked in for other sorts in this issue.
• The adjacent-order check switched from collection[index - 1] <= collection[index] (which requires __le__) to not collection[index] < collection[index - 1], so the algorithm relies on __lt__ alone — same behavior, weaker protocol requirement.
• New doctests: floats and ints sort in place together, and rec_insertion_sort([1, "a"], 2) raises TypeError (a silent mis-sort would be a correctness bug).

Verification:

$ uvx ruff check sorts/recursive_insertion_sort.py
All checks passed!

$ python -m pytest tests/test_sorts.py -q --no-header
444 passed in 0.37s

$ python -m pytest --doctest-modules sorts/recursive_insertion_sort.py -q --no-header
1 passed in 0.02s

The [3, 2, 3] and [3, 2, 4, 2] doctests are unchanged, so equal-element behavior is preserved.

Best,
Sam | Lead Engineer
DevilX Digital Labs
https://devilx-solution.vercel.app/