Remove extra "what" (#33383)

Fix #33369

Author: dawei-wang

docs/core/whats-new/dotnet-7.md

@@ -71,7 +71,7 @@ Many improvements have been made to .NET library APIs. Some are mentioned in oth
 | New type converters for `DateOnly`, `TimeOnly`, `Int128`, `UInt128`, and `Half` | In the <xref:System.ComponentModel?displayProperty=fullName> namespace:<br /><br />- <xref:System.ComponentModel.DateOnlyConverter><br />- <xref:System.ComponentModel.TimeOnlyConverter><br />- <xref:System.ComponentModel.Int128Converter><br />- <xref:System.ComponentModel.UInt128Converter><br />- <xref:System.ComponentModel.HalfConverter> | Type converters are often used to convert value types to and from a string. These new APIs add type converters for types that were added more recently. |
 | Metrics support for <xref:Microsoft.Extensions.Caching.Memory.IMemoryCache> | - <xref:Microsoft.Extensions.Caching.Memory.MemoryCacheStatistics><br />- <xref:Microsoft.Extensions.Caching.Memory.MemoryCache.GetCurrentStatistics?displayProperty=nameWithType> | <xref:Microsoft.Extensions.Caching.Memory.MemoryCache.GetCurrentStatistics> lets you use event counters or metrics APIs to track statistics for one or more memory caches. For more information, see the [.NET 7 Preview 4](https://devblogs.microsoft.com/dotnet/announcing-dotnet-7-preview-4/#added-metrics-for-microsoft-extensions-caching) blog post. |
 | APIs to get and set Unix file permissions | - <xref:System.IO.UnixFileMode?displayProperty=fullName> enum<br />- <xref:System.IO.File.GetUnixFileMode%2A?displayProperty=nameWithType><br />- <xref:System.IO.File.SetUnixFileMode%2A?displayProperty=nameWithType><br />- <xref:System.IO.FileSystemInfo.UnixFileMode?displayProperty=nameWithType><br />- <xref:System.IO.Directory.CreateDirectory(System.String,System.IO.UnixFileMode)?displayProperty=nameWithType><br />- <xref:System.IO.FileStreamOptions.UnixCreateMode?displayProperty=nameWithType> | For more information, see the [.NET 7 Preview 7](https://devblogs.microsoft.com/dotnet/announcing-dotnet-7-preview-7/#support-for-unix-file-modes) blog post. |
-| Attribute to indicate what what kind of syntax is expected in a string | <xref:System.Diagnostics.CodeAnalysis.StringSyntaxAttribute> | For example, you can specify that a `string` parameter expects a regular expression by attributing the parameter with `[StringSyntax(StringSyntaxAttribute.Regex)]`. |
+| Attribute to indicate what kind of syntax is expected in a string | <xref:System.Diagnostics.CodeAnalysis.StringSyntaxAttribute> | For example, you can specify that a `string` parameter expects a regular expression by attributing the parameter with `[StringSyntax(StringSyntaxAttribute.Regex)]`. |
 | APIs to interop with JavaScript when running in the browser or other WebAssembly architectures | <xref:System.Runtime.InteropServices.JavaScript?displayProperty=fullName> | JavaScript apps can use the expanded WebAssembly support in .NET 7 to reuse .NET libraries from JavaScript. For more information, see [Use .NET from any JavaScript app in .NET 7](https://devblogs.microsoft.com/dotnet/use-net-7-from-any-javascript-app-in-net-7/). |
 
 ## Observability