📚 Minor typo in `cross-referencing.md` #1750

Job	Run time
Check myst-docutils install (0.19)	12s
Check myst-docutils install (0.20)	14s
pre-commit	19s
Check myst-docutils install (0.21)	11s
pytest: py3.10, sphinx>=8,<9, on ubuntu-latest	35s
pytest: py3.11, sphinx>=8,<9, on ubuntu-latest	30s
pytest: py3.12, sphinx>=8,<9, on ubuntu-latest	37s
pytest: py3.13, sphinx>=8,<9, on ubuntu-latest	46s
pytest: py3.10, sphinx>=7,<8, on ubuntu-latest	44s
pytest: py3.10, sphinx>=7,<8, on windows-latest	1m 13s
check	1s
Publish myst-parser to PyPi	0s
Publish myst-docutils to PyPi	0s
	5m 22s

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