Corrected "docker-root" config key to "data-root"

[chopra5593]

"docker-root" is incorrect. The config key to change the docker location is "data-root"

[learn-build-service-prod]

Learn Build status updates of commit f0e0abd:

✅ Validation status: passed

File	Status	Preview URL	Details
virtualization/windowscontainers/manage-containers/container-storage.md	✅Succeeded

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