create include for doc providerin DI (#35427)

Author: tdykstra

aspnetcore/release-notes/aspnetcore-10/includes/doc-provider-in-di.md

@@ -0,0 +1,6 @@
+## Support for IOpenApiDocumentProvider in the DI container.
+<!-- https://github.com/dotnet/aspnetcore/pull/61463 -->
+ASP.NET has added support for `IOpenApiDocumentProvider` in the DI container.
+This allows you to inject the `IOpenApiDocumentProvider` into your application and use it to access the OpenAPI document.
+This is useful for scenarios where you need to access the OpenAPI document outside of the context of an HTTP request,
+such as in a background service or a custom middleware.