Fix various issues in response to UUF feedback

[gewarren]

Hide whitespace changes.

[dotnet-policy-service]

Tagging subscribers to this area: @dotnet/area-system-text-regularexpressions

[learn-build-service-prod]

Learn Build status updates of commit c027928:

✅ Validation status: passed

File	Status	Preview URL	Details
snippets/csharp/System.Text.RegularExpressions/Regex/IsMatch/ismatch1.cs	✅Succeeded	View
snippets/csharp/System.Text.RegularExpressions/Regex/IsMatch/ismatch2.cs	✅Succeeded	View
snippets/csharp/System.Text.RegularExpressions/Regex/IsMatch/ismatch3.cs	✅Succeeded	View
snippets/csharp/System.Text.RegularExpressions/Regex/IsMatch/ismatch4.cs	✅Succeeded	View
snippets/csharp/System.Text.RegularExpressions/Regex/IsMatch/ismatch5.cs	✅Succeeded	View
snippets/csharp/System.Text.RegularExpressions/Regex/IsMatch/Project.csproj	✅Succeeded
xml/System.Net/HttpWebRequest.xml	✅Succeeded	View
xml/System.Windows.Forms/DataGridView.xml	✅Succeeded	View
xml/System/Char.xml	✅Succeeded	View
xml/System/Decimal.xml	✅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

[BillWagner]

This LGTM @gewarren

You can once you and the product team are ready.