fix: handle empty input in jump_search

[pony-maggie]

Describe your change:

Fixed jump_search([], item) so it returns -1 instead of raising IndexError.

Why

The function documents -1 as the result when the item is not found. An empty collection is a valid not-found case and should not attempt to index into the sequence.

How tested

• RED: /opt/homebrew/opt/python@3.14/bin/python3.14 -m doctest -v searches/jump_search.py failed with IndexError before the fix
• /opt/homebrew/opt/python@3.14/bin/python3.14 -m doctest -v searches/jump_search.py
• /tmp/thealgorithms-py314-pytest/bin/python -m pytest --doctest-modules searches/jump_search.py -q
• Randomized comparison against expected search results for 200 generated sorted lists
• git diff --check

• 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".

[priya-sundaram-dev]

Correct edge-case fix: jump_search([], item) previously computed block_size = int(math.sqrt(0)) = 0 and could loop/misbehave; returning -1 for an empty array is the right contract and matches the "not found" return. Doctest added, CI green. LGTM ✅

Note for the maintainers: #15101 is an identical fix to the same function — this one (#14807) came first, so I'd suggest merging this and closing #15101 as a duplicate.