Fix split function to handle trailing delimiters correctly

[kishyassin]

This pull request includes enhancements to the split function in the strings/split.py file to handle cases where the separator appears at the end of the input string. The most important changes include adding new test cases and modifying the function logic to append an empty string when the input string ends with the separator.

Enhancements to split function:

• strings/split.py: Added a test case for input strings where the separator appears at the beginning and end of the string.

• strings/split.py: Modified the function logic to append an empty string to the result list if the input string ends with the separator.### Describe your change:

• Add an algorithm?

• [x ] 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:

• [x ] I have read CONTRIBUTING.md.
• [x ] This pull request is all my own work -- I have not plagiarized.
• [ x] I know that pull requests will not be merged if they fail the automated tests.
• [x ] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• [x ] All new Python files are placed inside an existing directory.
• [ x] All filenames are in all lowercase characters with no spaces or dashes.
• [x ] All functions and variable names follow Python naming conventions.
• [ x] All function parameters and return values are annotated with Python type hints.
• [ x] All functions have doctests that pass the automated testing.
• [x ] All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• [x ] If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes strings/split.py is incorrect #12403 ".

[imSanko]

Could you please discuss the changes you wanna commit to?

[kishyassin]

@imSanko Fixes #12403 ".