build: add python 3.12 checks alongside 3.8

[DawoudSheraz]

For #1006

Description

• Adds Python 3.12 checks in CI alongside 3.8
• Fix make docs in Python 3.12

make docs in Python 3.12 was failing for various reasons for variety of items (Action, Filter, FilterCallbackFunc). Mainly, the generic type does not get translated to py:class and is instead picked up as py:data. There were a few issues on Sphinx and some related items on Stackoverflow. Everyone handled it differently in some capacity. One suggestion was to ignore some of the type params but it did not result in docs building as expected (#1008 (comment)). The appropriate fix for "Action & Filter" was to add entries in autodoc_type_aliases. FilterCallbackFunc was needed to be ignore because it does not translate to a py:class.

[DawoudSheraz]

The docs build failure seems to be an old one #775 (comment). I will attempt a shot at fixing it.

[DawoudSheraz]

The docs build issue mainly happens because Sphinx is not able to correctly identify type params. It tends to translate each param variation into a separate py:class entity, thus leading into errors when running in nitpick mode. One of the ways was to ignore the patterns via nitpick_ignore_regex but it resulted in docs not building as expected.

• https://docs.plasmapy.org/en/stable/contributing/doc_guide.html#reference-target-not-found
• Use of TypeVar results in "reference target not found" error sphinx-doc/sphinx#10974
• autodoc-documented type aliases can't be referenced from type annotations sphinx-doc/sphinx#10785

[regisb]

Remove changelog entry and we are good to go.

[regisb]

CI-only changes don't warrant a changelog.

Basically, to decide whether a change needs a changelog entry, we need to place ourselves in the position of the typical Tutor user: platform administrator or plugin developer. Whenever they upgrade, we expect that they have a look at the changelog entries. We don't want them to worry unnecessarily about changes that won't impact them. But we do want to highlight the features that they might want to use and the breaking changes.

[DawoudSheraz]

Ok.

[regisb]

lgtm!