Fix/tree sort iterable type hint

[DrishtiTripathi2230]

Describe your change:

Improve type hint for tree_sort to accept any Iterable[int] instead of only list[int], and enable the previously commented-out range doctest.

• 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.
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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".

[diusazzad]

provided a fix for iterable type hint

[diusazzad]

Hey @DrishtiTripathi2230! Thanks for taking the time to improve the type hints! 🚀

Changing the type hint to Iterable[int] is a great idea conceptually. However, it introduces a subtle bug. Since Iterable includes generators, passing a generator will cause the code to crash because:

1. len(arr) will raise a TypeError (generators have no len()).
2. arr[0] and arr[1:] will also raise a TypeError (generators are not subscriptable).

To fix this and fully support any Iterable, we can convert the iterable into an iterator using iter(). Here is a suggested fix for the logic inside the function:

def tree_sort(arr: Iterable[int]) -> tuple[int, ...]:
    # ... docstrings ...
    iterator = iter(arr)
    try:
        first = next(iterator)
    except StopIteration:
        return ()
        
    root = Node(first)
    for item in iterator:
        root.insert(item)
    return tuple(root)