(GH-10127) Document enums as function parameters

[michaeltlombardi]

PR Summary

Prior to this change, the about_Enum topic showed using enumerations in scripts but not as parameters.

This change:

• Adds a new section to the article, clarifying the benefits of using enumerations as parameter types and including an example.
• Cleans up the prose and formatting for the article.
• Documents using the HasFlag() method as an alternative to using the binary comparison operator.
• Resolves Passing Enums as Function Parameters #10127
• Fixes AB#97124

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 84ed2ae:

✅ Validation status: passed

File	Status	Preview URL	Details
reference/5.1/Microsoft.PowerShell.Core/About/about_Enum.md	✅Succeeded	View (powershell-5.1)
reference/7.2/Microsoft.PowerShell.Core/About/about_Enum.md	✅Succeeded	View (powershell-7.2)
reference/7.3/Microsoft.PowerShell.Core/About/about_Enum.md	✅Succeeded	View (powershell-7.3)
reference/7.4/Microsoft.PowerShell.Core/About/about_Enum.md	✅Succeeded	View (powershell-7.4)

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