Fix Bug [#14844] : Boyer-Moore bad character shift has no effect (for-loop variable reassignment)

[Divyanshu-hash]

Describe your change:

In strings/boyer_moore_search.py, the bad_character_heuristic() method attempts to skip positions using the bad character rule, but the shift has no effect because it reassigns the for-loop variable i. In Python, reassigning the loop variable inside a for loop does not change the iteration, meaning the algorithm was behaving as brute-force O(nm) instead of Boyer-Moore O(n/m).

This PR fixes the bug by replacing the for loop with a while loop, allowing the shift to take effect. It also adds a max() guard to ensure the algorithm never shifts backwards, and expands the doctests to cover non-matching and overlapping edge cases.

• 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.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes Bug: Boyer-Moore bad character shift has no effect (for-loop variable reassignment) #14844".