MAINT: clean up Sphinx configuration #268

Job	Run time
pytest / Determine job matrix	6s
style / Determine skipped pre-commit hooks	6s
doc / nb / Execute and build documentation	1m 23s
doc / linkcheck / Check external links	1m 37s
style / Run local pre-commit hooks	1m 51s
style / Run taplo through pre-commit	28s
pytest / Run unit tests (3.10, ubuntu-22.04)	1m 11s
pytest / Run unit tests (3.11, ubuntu-22.04)	54s
pytest / Run unit tests (3.12, ubuntu-22.04)	1m 12s
pytest / Run unit tests (3.7, ubuntu-22.04)	1m 10s
pytest / Run unit tests (3.9, ubuntu-22.04)	1m 4s
pytest / Run unit tests (3.8, ubuntu-22.04, ampform)	1m 56s
pytest / Run unit tests (3.9, macos-12)	1m 34s
doc / Upload to GitHub Pages	0s
style / Push changes	0s
	14m 32s

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