Feat(range_parse): support mixed port list and range combinations (#835)

[RaghavendraRQ]

This PR adds support for parsing mixed port specifications that combine individual ports and ranges within the same -p argument.

Previous Behaviour
RustScan accepted a single range of ports (100-1000).

New Behaviour
Users can now specify ports using a flexible syntax that supports Multi-range ports
rustscan --range 100-200,300-400 $IP'

Implementation Details
input.rs -- parse_range validation; [Opts.range] -> Option<Vec>; config handling and defaults updated; tests adjusted
mod.rs -- pick -> updated to accept multiple ranges and expand them into a Manual port list for multi-range input
mod.rs -- & lib.rs — tests and doctest updated to use the new API where necessary

Testing done

Updated unit tests and doctests run locally: cargo test - (all tests passed)
Existing behaviour retained for single-range or --ports inputs