A new way of supporting plugins was added as part of https://github.com/microsoft/typespec/pull/10249/changes#diff-d9df131d69d8ac200e99295364c47ff110093a4f5104a7328d191c33dd57e4c4. We should add a small doc with examples so emitter authors can follow to create their own plugin. We should add this to our existing docs https://github.com/microsoft/typespec/tree/main/packages/http-client-csharp/docs