Previously, a NullPointerException would occur if
endpoints.docs.curies.enabled was true and the default value was being
used for either server.port or management.port.

EndpointWebMvcHypermediaManagementContextConfiguration has been
restructured to ensure that the DocsMvcEndpoint bean is defined before
the condition on its existence is evaluated. Previously this was
dependant on the class’s bean methods being processed in a particular
ordering, something that would be ok when using ASM but would vary when
using reflection.

Closes gh-6584

Closes gh-6567
See gh-6583

Closes gh-6552

* pr/6580:
  Polish contribution
  Add reference to Apache CXF integration

Closes gh-6580

See gh-6580

Update JsonTestersAutoConfiguration so that GSON and Jackson specific
configuration are inner classes. This should prevent ClassNotFound
exception when the libraries are not on the classpath.

Fixes gh-6502

See gh-6534

* pr/6492:
  Fix `spring-boot-legacy` version

Closes gh-6492

* pr/6534:
  Polish contribution
  Fix aliases for database names in `JdbcSessionDatabaseInitializer`

Closes gh-6534

See gh-6354

This commit uses maven filtering to set the Groovy version rather than an
hard-coded value that can be easily outdated.

Closes gh-6530

Closes gh-6518

Closes gh-6499

This commit fixes the `@ConditionalOnClass` typo on the GsonTester
FactoryBean, which was testing for `ObjectMapper` instead of `Gson`.

This means that the next condition `@ConditionalOnBean(Gson.class)`
throws a `ClassNotFoundException: com.google.gson.Gson` since it's
trying to load that class to check for an existing Bean of that type.

Fixes gh-6502

Update spring-boot-docs so that an empty jar file is produced. The
code is only needed for documentation includes and if included in the
deployed jar seems to prevent promotion to Maven Central.

Fixes gh-6495

Closes gh-6318

Update ConfigurationPropertiesBindingPostProcessor with improved logging
when multiple PropertySourcesPlaceholderConfigurer beans are found.

See gh-6457

Replace `@UnmappedPropertyValue` with a `skip` attribute on
`@PropertyMapping` so that any default attribute value can be skipped.

Closes gh-6455

Closes gh-6490

* pr/6486:
  Add WireMock Spring Boot starter reference

Closes gh-6486

* gh-6487:
  Polish

Closes gh-6487

* pr/6461:
  Update Gradle remote debug documentation

Update the documentation to reference the `bootRun` command rather
than `run`.

Closes gh-6461

Update the reference documentation and add some additional Javadoc to
provide hints on how to customize the `TestRestTemplate`.

Fixes gh-6465