See gh-13790

* pr/13790:
  Polish contribution
  Polish

See gh-13790

See gh-13790

* pr/13792:
  Add missing @Test in RestarterTests

Closes gh-13792

This commit turns a lazy injection point for `HttpMessageConverters`
into an `ObjectProvider`-backed injection.

This allows to lazily rely on that bean without creating for it; in some
environments, such proxy creation can lead to issues like SPR-16990.

See gh-13785

* pr/13779:
  Remove carriage returns in TypeUtils.getJavaDoc()

Closes gh-13779

Closes gh-13782

* pr/13582:
  Polish "Allow to configure Quartz's "overwriteExistingJobs" property"
  Allow to configure Quartz's "overwriteExistingJobs" property

Closes gh-13582

See gh-13582

This is required for the docs module to inspect Spring Boot
annotations for meta-annotations.

See gh-13739

* pr/13778:
  Fix since on JdbcOperationsDependsOnPostProcessor

Closes gh-13778

Since SPR-17034, the core container now behaves a bit differently when
dealing with `null` beans.

Given a `null` `HandlerMapping` bean named "resourceHandlerMapping":

* `context.getBean("resourceHandlerMapping", HandlerMapping.class)`
still returns a `NullBean`
* `ListableBeanFactory.getBeansOfType` will return a Map of all existing
beans, not including the `null` ones as values of the map.

Closes gh-13760

* pr/13776:
  Polish

Closes gh-13776

* pr/13776:
  Polish

See gh-13776

* pr/13774:
  Remove a List creation in CompositePropertySources.iterator()

Closes gh-13774

See gh-13722

Closes gh-13722

Closes gh-13765

Closes gh-13744

* pr/13625:
  Polish "Upgrade to Liquibase 3.6.2"
  Upgrade to Liquibase 3.6.2

Closes gh-13625