Fix "AKV management client library for .NET" page

[xakep139]

Right now the page looks like this:

[xakep139]

Even on GitHub this list in resourcemanager.keyvault-readme.md is shown as a code block:

[learn-build-service-prod]

Learn Build status updates of commit 2222958:

⚠️ Validation status: warnings

File	Status	Preview URL	Details
api/overview/azure/latest/resourcemanager.keyvault-readme.md	⚠️Warning	View (azure-dotnet)	Details

api/overview/azure/latest/resourcemanager.keyvault-readme.md

• Line 2, Column 1: [Warning: title-missing - See documentation] Missing required attribute: 'title'. Add a title string to show in search engine results.
• Line 9, Column 13: [Warning: ms-service-subservice-invalid - See documentation] Invalid value for 'ms.service': 'keyvault'.
• Line 2, Column 1: [Suggestion: description-missing - See documentation] Missing required attribute: 'description'.
• Line 56, Column 3: [Suggestion: preserve-view-not-set - See documentation] You've pinned this link to a specific version of content with the view parameter. It's recommended not to pin a version unless that version is A) not the default view and B) the context is about that version specifically. To proceed with pinning a version add the &preserve-view=true to the URL. Otherwise, remove the view parameter. URL: /dotnet/api/?view=azure-dotnet
• Line 62, Column 3: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://learn.microsoft.com/samples/browse/?branch=master&languages=csharp&term=managing%20using%20Azure%20.NET%20SDK' will be broken in isolated environments. Replace with a relative link.

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