Spring Align javadoc of DefaultParameterNameDiscoverer with its behavior

As far as I can tell, the changes made in https://github.com/spring-projects/spring-framework/commit/c4e8ffece16db679ef4d92d97d7b3e8c748f0b5a left the javadoc of DefaultParameterNameDiscoverer out of alignment with its behavior. Assuming that I haven't missed KotlinReflectionParameterNameDiscoverer being skipped by some other mechanism, this PR align things again.

Comment From: snicoll

Closed by https://github.com/spring-projects/spring-framework/commit/37b439182e4aacf48b33d9c1ad3201a2ef5a6f13