Improved code complexity for segmented sieve

[heartsker]

Describe your change:

Improved code complexity for segmented sieve - segmented_sieve.py

Tested code complexity using radon tool

Previously the CC rank was C, now it is B

To check the improvement use

radon cc Python/maths/segmented_sieve.py -a 

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• 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 have a URL in its comments that points to Wikipedia or other similar explanation.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[poyea]

It would be nice if we could have some tests around this, say len(sieve(10**6) == 78498. Also it would be better to have timeit to show that it's using less computing time.

[poyea]

Thank you for your pull request!🤩