Update new types with links

[Rick-Anderson]

Description

add <xref:> links for all new types. For example, AddOpenApi

Look for links of the form https://source.dot.net/ and replace with <xref:> links

Page URL

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/minimal-apis/aspnetcore-openapi?branch=main&branchFallbackFrom=pr-en-us-32688&view=aspnetcore-9.0

Content source URL

https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/fundamentals/minimal-apis/aspnetcore-openapi.md

Document ID

d515a3d8-28f2-578f-c302-dc884544aaf4

Article author

@captainsafia

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Associated WorkItem - 258797