Freshness: .NET tutorials

[meaghanlewis]

Describe the issue or suggestion

Freshness pass on .NET tutorials: https://github.com/dotnet/docs/tree/main/docs/core/tutorials.

• Check for accuracy and up-to-date details in code.
• Check verbatim comments for the tutorials.
• Check for GitHub issues for the tutorials.
• Check that all links go to current, accurate, and relevant content.
• Fix all grammar and spelling and style issues.

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Associated WorkItem - 492215