Fix typo in example of passing a callable to markers

[ghost]

Thanks for submitting a PR, your contribution is really appreciated!

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• Add a new news fragment into the changelog folder
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[coveralls]

Changes Unknown when pulling e27a0d6 on xuanluong:pass-callable-to-marker-typo into ** on pytest-dev:master**.

[coveralls]

Coverage remained the same at 91.805% when pulling e27a0d6 on xuanluong:pass-callable-to-marker-typo into 3c1ca03 on pytest-dev:master.

[nicoddemus]

Thanks!