[docs/python] Complex types are rendered poorly by Sphinx

[ebezzi]

Some types (especially union types) are rendered by Sphinx in a confusing way:

Find out if they can be simplified. Ideally, the type in question should not be expanded but instead link to its definition.

[thetorpedodog]

this is unfortunate and rather unhelpful, but extremely funny

[johnkerl]

Support is not live yet:

• Break long function declarations into one parameter per line sphinx-doc/sphinx#1514
• ENH: enable multiline signatures when too long. sphinx-doc/sphinx#11011

It remains to be seen whether this will land in Sphinx before or after we move from Sphinx to Quarto (#1055).

[johnkerl]

We can do no more in this sprint, but I'm leaving this issue open until (a) the above Sphinx feature lands, or (b) this issue is obviated by #1055.

[johnkerl]

To be resolved by #1055

[johnkerl]

Obviated by #1055