Over the years we have introduced documentation such as "since JUnit Jupiter 5.4", etc. in numerous places in Javadoc and the User Guide.

However, for JUnit 6, users will likely not be interested in the fact that a feature was introduced or changed in JUnit 5.1, 5.4, 5.7, etc.

Though, they may be interested in changes as recent as 5.13.

In light of that, we should revise the User Guide and Javadoc to only point out previous versions of JUnit that aren't too "old".