[UUF] Fix bracket indentation

[gewarren]

• Fix bracket indentation
• Modernize code

[dotnet-policy-service]

Tagging subscribers to this area: @dotnet/area-system-runtime

[learn-build-service-prod]

Learn Build status updates of commit 6543e72:

✅ Validation status: passed

File	Status	Preview URL	Details
snippets/csharp/System/DateTime/ToString/tostring.csproj	✅Succeeded
snippets/csharp/System/DateTime/ToString/ToString4.cs	✅Succeeded	View

For more details, please refer to the build report.

For any questions, please:

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• Post your question in the Learn support channel

[BillWagner]

I agree with Tanner's formatting comment, and then this is ready to merge.

[learn-build-service-prod]

Learn Build status updates of commit a59f422:

✅ Validation status: passed

File	Status	Preview URL	Details
snippets/csharp/System/DateTime/ToString/tostring.csproj	✅Succeeded
snippets/csharp/System/DateTime/ToString/ToString4.cs	✅Succeeded	View

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel