Update docs for visualization tutorial

[VictorForouhar]

I tried following the visualization tutorial, but it seems that it was outdated. My installed version is 8.0.1 (I know, I should update).

[VictorForouhar]

I ran the formatter and ran pytest. No issues aside from a warning from SOAP-related code, which I did not modify in my changes.

====================================================================================== warnings summary =======================================================================================
tests/test_soap.py::test_soap_can_mask_spatial_and_non_spatial_actually_use
  /snap8/scratch/dp004/dc-foro1/swiftsimio_test/swiftsimio/swiftsimio/objects.py:273: RuntimeWarning: Mixing ufunc arguments with and without cosmo_factors, continuing assuming provided cosmo_factor (1 at a=0.9999999999999994) for all arguments.
    warnings.warn(

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
========================================================================= 105 passed, 1 warning in 145.72s (0:02:25) ==========================================================================