Fix missing descriptions

[sdwheeler]

PR Summary

Fix missing descriptions

• Fixes AB#446504

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 contributor's guide.
• Style: This PR adheres to the style guide.

[learn-build-service-prod]

Learn Build status updates of commit 6c073be:

✅ Validation status: passed

File	Status	Preview URL	Details
reference/5.1/Microsoft.PowerShell.Security/Unprotect-CmsMessage.md	✅Succeeded	View (powershell-5.1)
reference/7.4/Microsoft.PowerShell.Security/Unprotect-CmsMessage.md	✅Succeeded	View (powershell-7.4)
reference/7.5/Microsoft.PowerShell.Management/Join-Path.md	✅Succeeded	View (powershell-7.5)
reference/7.5/Microsoft.PowerShell.Security/Unprotect-CmsMessage.md	✅Succeeded	View (powershell-7.5)
reference/7.6/Microsoft.PowerShell.Security/Unprotect-CmsMessage.md	✅Succeeded	View (powershell-7.6)

For more details, please refer to the build report.