Update Javadoc to stop mentioning 5.3.x as the status quo

[sbrannen]

Several annotations in the spring-test module contain Javadoc similar to the following.

As of Spring Framework 5.3, this annotation will be inherited from an enclosing test class by default. See @NestedTestConfiguration for details.

Since this feature has existed for several years now, we should remove the "As of Spring Framework 5.3" clause in order to reduce noise and unnecessary confusion (mental overhead) going forward.

After looking a little deeper, I realized that we have a lot of Javadoc that effectively refers to 5.2.x/5.3.x as the status quo. So, we should update all affected documentation.