Fix typo in _memory.pyx docstring

[ndgrigorian]

This PR proposes a very small fix to a typo in a docstring in _memory.pyx

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[github-actions]

Deleted rendered PR docs from intelpython.github.com/dpctl, latest should be updated shortly. 🤞

[github-actions]

Array API standard conformance tests for dpctl=0.20.0dev0=py310h93fe807_182 ran successfully.
Passed: 1109
Failed: 3
Skipped: 119

[coveralls]

coverage: 86.363%. remained the same
when pulling 796831d on fix-typo-in-memory
into 8df03aa on master.