docs(python): Use .with_columns() in all .list namespace examples

[cmdlineluser]

Not sure if I need to make an issue for this first:

I noticed .select() was used when checking the docs for .list.join so I thought I'd update all the examples.

A couple of other changes:

• replaced all .alias() calls with named expressions
• a few examples used pl.Series so I changed them to pl.DataFrame
• .list.take() had no example, so I added one
• I added some max_width examples/notes to .list.to_struct()

[alexander-beedie]

I think this is a great improvement! Increasing the use of with_columns in the examples really helps to make it clear exactly what is happening... Gets my vote (with just one minor update) 😎👍