Fixup OpenAPI content in Whats New doc (#33999)

* Fixup OpenAPI content in Whats New doc
* Address comments from PR review

Author: mikekistler

aspnetcore/release-notes/aspnetcore-9.0.md

@@ -45,14 +45,8 @@ This section describes new features for OpenAPI
 
 [!INCLUDE[](~/release-notes/aspnetcore-9/includes/openApi.md)]
 
-[!INCLUDE[](~/release-notes/aspnetcore-9/includes/openAPI_completion.md)]
-
-[!INCLUDE[](~/release-notes/aspnetcore-9/includes/transformer-registration.md)]
-
 [!INCLUDE[](~/release-notes/aspnetcore-9/includes/openapi-aot.md)]
 
-[!INCLUDE[](~/release-notes/aspnetcore-9/includes/prob_validation.md)]
-
 ## Authentication and authorization
 
 This section describes new features for authentication and authorization.

aspnetcore/release-notes/aspnetcore-9/includes/openApi.md

@@ -1,6 +1,6 @@
 ### Built-in support for OpenAPI document generation
 
-The [OpenAPI specification](https://www.openapis.org/) is a standard for describing HTTP APIs. The standard allows developers to define the shape of APIs that can be plugged into client generators, server generators, testing tools, documentation, and more. In .NET 9 Preview, ASP.NET Core provides built-in support for generating OpenAPI documents representing controller-based or minimal APIs via the [Microsoft.AspNetCore.OpenApi](https://nuget.org/packages/Microsoft.AspNetCore.OpenApi) package.
+The [OpenAPI specification](https://www.openapis.org/) is a standard for describing HTTP APIs. The standard allows developers to define the shape of APIs that can be plugged into client generators, server generators, testing tools, documentation, and more. In .NET 9, ASP.NET Core provides built-in support for generating OpenAPI documents representing controller-based or minimal APIs via the [Microsoft.AspNetCore.OpenApi](https://nuget.org/packages/Microsoft.AspNetCore.OpenApi) package.
 
 The following highlighted code calls:
 
@@ -25,14 +25,14 @@ OpenAPI documents can also be generated at build-time by adding the [`Microsoft.
 dotnet add package Microsoft.Extensions.ApiDescription.Server --prerelease
 ```
 
-In the app's project file, add the following:
+To modify the location of the emitted OpenAPI documents, set the target path in the OpenApiDocumentsDirectory property in the app's project file:
 
-:::code language="xml" source="~/release-notes/aspnetcore-9/samples/OpenApiExample/OpenApiExample.csproj" range="9-12":::
+:::code language="xml" source="~/release-notes/aspnetcore-9/samples/OpenApiExample/OpenApiExample.csproj" range="9-11":::
 
 Run `dotnet build` and inspect the generated JSON file in the project directory.
 
 ![OpenAPI document generation at build-time](~/release-notes/aspnetcore-9/_static/openapidoc2.png)
 
-ASP.NET Core's built-in OpenAPI document generation provides support for various customizations and options. It provides document and operation transformers and has the ability to manage multiple OpenAPI documents for the same application.
+ASP.NET Core's built-in OpenAPI document generation provides support for various customizations and options. It provides document, operation, and schema transformers and has the ability to manage multiple OpenAPI documents for the same application.
 
 To learn more about ASP.NET Core's new OpenAPI document capabilities, see [the new Microsoft.AspNetCore.OpenApi docs](https://aka.ms/aspnet/openapi).

aspnetcore/release-notes/aspnetcore-9/includes/prob_validation.md

@@ -15,3 +15,11 @@ app.Run();
 
 record Todo(int Id, string Title, boolean IsCompleted);
 ```
+
+### `Problem` and `ValidationProblem` result types support construction with `IEnumerable<KeyValuePair<string, object?>>` values
+
+Prior to .NET 9, constructing [Problem](/dotnet/api/microsoft.aspnetcore.http.typedresults.problem) and [ValidationProblem](/dotnet/api/microsoft.aspnetcore.http.typedresults.validationproblem) result types in minimal APIs required that the `errors` and `extensions` properties be initialized with an implementation of `IDictionary<string, object?>`. In this release, these construction APIs support overloads that consume `IEnumerable<KeyValuePair<string, object?>>`.
+
+:::code language="csharp" source="~/fundamentals/openapi/samples/9.x/ProducesProblem/Program.cs" id="snippet_2" :::
+
+Thanks to GitHub user [joegoldman2](https://github.com/joegoldman2) for this contribution!

aspnetcore/release-notes/aspnetcore-9/includes/produces-problem.md

@@ -8,9 +8,8 @@
 
   <PropertyGroup>
     <OpenApiDocumentsDirectory>$(MSBuildProjectDirectory)</OpenApiDocumentsDirectory>
-    <OpenApiGenerateDocuments>true</OpenApiGenerateDocuments>
   </PropertyGroup>
-  
+
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="9.0.0-preview.5" />
   </ItemGroup>