Spring Fix and improve Javadoc in spring-tx

Comment From: marcwrobel

@sbrannen, thank you for you reviews. For the time being I create a PR for each module. But if it is easier for you I can make bigger PRs (with 2-3 modules in each).

Comment From: sbrannen

But if it is easier for you I can make bigger PRs (with 2-3 modules in each).

2-3 modules per PR would help.

Also, please based the PRs on 5.3.x instead of main.

Thanks.