fix(inventory): fix `RemovedInSphinx10Warning` #1936

Job	Run time
pre-commit	14s
Check myst-docutils install (0.20)	15s
Check myst-docutils install (0.21)	10s
pytest: py3.11, sphinx>=8,<9, on ubuntu-latest	31s
pytest: py3.14, sphinx>=8,<9, on windows-latest	1m 19s
pytest: py3.11, sphinx>=8,<9, on windows-latest	1m 17s
pytest: py3.13, sphinx>=8,<9, on ubuntu-latest	34s
pytest: py3.12, sphinx>=8,<9, on ubuntu-latest	34s
pytest: py3.14, sphinx>=8,<9, on ubuntu-latest	28s
check	2s
Publish myst-parser to PyPi	-1s
Publish myst-docutils to PyPi	0s
	5m 23s

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