Closes gh-15444

Since the transport client has been deprecated in gh-15008, the health
indicator for that should be deprecated as well.

See gh-15008

Closes gh-16529

Closes gh-16531

Closes gh-16569

This commit introduced an incompatible change in the asciidoct
API: both asciidoctorj-pdf and spring-asciidoctor-extensions
expect `org.asciidoctor.extension.JavaExtensionRegistry` to be
a class, not an interface.

This reverts commit 120ffb1e.

See gh-16021

Closes gh-16534

Closes gh-16567

Closes gh-16566

Closes gh-16532

Closes gh-16565

This commit improves the detection of a property source when more than
one group with the same type exist.

Closes gh-16549

Closes gh-16564

The move to an HTTPS URL for the xmlns:xslt identifier has the unwanted
side-effect of disabling indentation.

This commit moves back to an HTTPS URL. It also changes the indent size
to 2, aligning with the size used by all the other poms that are written
by the flatten plugin.

Closes gh-16466

Closes gh-16554

As of Spring Data Moore, the Elasticsearch high level REST client is
supported for Spring Data repositories. The transport client is now
deprecated and is likely to be removed in a future Spring Data release.

This commit deprecates the transport client and marks all the associated
configuration properties as deprecated. The Spring Boot starter depends
on the `spring-data-elasticsearch` project, which now depends on both
transport client and high level REST client.

This commit also deprecates the Jest client, as Spring Boot will focus
on supporting the high level REST client and the reactive client
provided by Spring Data - both being in sync with the fast release pace
of Elasticsearch.

Closes gh-15008

Closes gh-16510

Closes gh-16530

* pr/16554:
  Upgrade to Kotlin 1.3.30

Closes gh-16554

See gh-5677

Previously, if the `server.use-forward-headers` property
was set to true, X-Forwarded-* headers support was provided
at the server level. The property has been deprecated in favor
of `server.forward-headers-strategy` which can be also be configured
to use Spring's forwarded header support apart from native server support.

Closes gh-5677

Closes gh-16302

See gh-16021

Relax the `NettyRSocketBootstrap` contract to allow all types of
`SocketAcceptor` implementations.

See gh-16021

Closes gh-15952

See gh-15952

This commit adds support for RSocket server applications.
The auto-configuration will either add RSocket support to an existing
Reactor Netty server in a WebFlux application (as a WebSocket endpoint),
or bootstrap a brand new RSocket server instance.

Spring Boot will also auto-configure the Spring Messaging infrastructure
that supports Controller beans with `@MessageMapping` annotated methods.

Fixes gh-16021

Closes gh-16452

Closes gh-16528

* pr/16527:
  Fix package of java.time.Duration in documentation