This commit adds `application/*+x-ndjson`, a wildcard media type which
covers all types that can be parsed as nd-json, to the list of media
types the ReactiveTypeHandler considers for a streaming response in
WebMVC.
As a result, a request which for example `Accept` the
`application/vnd.myapp.v1+x-ndjson` media type will generate a response
with the same `Content-Type`, with newline-delimited json objects being
streamed in the response body.
Closes gh-26817
9332b3f690