Doc instructions for using JDK 21

[binkley]

I have a pleasure project (https://github.com/binkley/kotlin-dice) using Parboiled (latest, 1.4.1) that is presently stuck on JDK 11 tooling from the Parboiled dependency. Without result I search the Parboiled documentation for setup in this circumstance. Perhaps a hello-world setup project in this repo would help others?

Is there documentation I've missed? How does one use Parboiled with JDK 21? I see a recent commit to add tests for JDK 21, and reviewing that, I wonder if my issue is not Parboiled.

Note that I am using Maven. I haven't explored if Gradle "works out of the box".