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

See gh-13625

* pr/13706:
  Prevent duplicate RequestMatcher in RequestMatcherFactory.antPath()

Closes gh-13706

Closes gh-13601

* pr/13762:
  Fix typos

Closes gh-13762

* gh-13757:
  Remove @since tag from getServlet()

Closes gh-13757

This commit adapts to a recent Spring Framework change (a40d25a) that
turns no-op Spring MVC beans (infrastructure components that, given
their configuration, won't contribute anything to the application) into
`NullBean` instances.

* pr/13755:
  Fix typo