fixes typo in sanic-ext cors docs #668

Job	Run time
Linux / Python 3.8 / tox -e security	34s
Linux / Python 3.9 / tox -e security	28s
Linux / Python 3.10 / tox -e security	26s
Linux / Python 3.11 / tox -e security	22s
Linux / Python 3.10 / tox -e lint	29s
Linux / Python 3.8 / tox -e type-checking	36s
Linux / Python 3.9 / tox -e type-checking	28s
Linux / Python 3.10 / tox -e type-checking	32s
Linux / Python 3.11 / tox -e type-checking	32s
Linux / Python 3.8 / tox -e py38	3m 54s
Linux / Python 3.8 / tox -e py38-no-ext	3m 48s
Linux / Python 3.9 / tox -e py39	7m 14s
Linux / Python 3.9 / tox -e py39-no-ext	3m 42s
Linux / Python 3.10 / tox -e py310	3m 32s
Linux / Python 3.10 / tox -e py310-no-ext	3m 29s
Linux / Python 3.11 / tox -e py311	3m 22s
Linux / Python 3.12 / tox -e py312	3m 43s
Linux / Python 3.11 / tox -e py311-no-ext	3m 18s
Windows / Python 3.8 / tox -e py38-no-ext	4m 5s
Windows / Python 3.9 / tox -e py39-no-ext	4m 20s
Windows / Python 3.10 / tox -e py310-no-ext	4m 14s
Windows / Python 3.11 / tox -e py310-no-ext	4m 52s
	58m 0s

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