Fully describe existing parameters in Set-MpPreference

[chrisda]

PR Summary

Fixes https://dev.azure.com/msft-skilling/Content/_workitems/edit/327882.

PR Checklist

• Descriptive Title: This PR's title is a synopsis of the changes it proposes.
• Summary: This PR's summary describes the scope and intent of the change.
• Contributor's Guide: I have read the contributors guide.
• Style: This PR adheres to the style guide.

[learn-build-service-prod]

Learn Build status updates of commit b91ac6e:

✅ Validation status: passed

File	Status	Preview URL	Details
docset/winserver2022-ps/defender/Set-MpPreference.md	✅Succeeded	View (WindowsServer2022-ps)

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