Support step parameter in slice_assign method

### Feature Request

Currently, the `slice_assign` method in the repository does not support a `step` parameter, limiting its flexibility for advanced slicing operations. Adding support for the `step` parameter would allow users to perform more complex slice assignments similar to standard Python and NumPy slicing.

**Proposed Solution:**
- Update the `slice_assign` method to accept and handle a `step` parameter.
- Ensure proper validation and error handling for different step values (positive, negative, zero).
- Add tests to verify correct behavior with various step values.
- Update documentation to reflect the new parameter and provide usage examples.