This uses Gradle's auto-provisioning to compile Java 19 classes and build a multi-release JAR from them. Please make sure to regenerate gradle.properties (delete it) or change "org.gradle.java.installations.auto-download" to "true"
Previously -Xlint:text-blocks and -Xlint:text-blocks were enabled
conditionally, if the user had at least java 15 or java 16,
respectively. Enable them always.
Add new options so that the warnings list is fully configured:
* -Xlint:module (new in java 17)
* -Xlint:strictfp (new in java 17)
Disable "path" with -Xlint:-path rather than commenting it out, for
consistency.
Disable "missing-explicit-ctor" (new in java 17), as it is unlikely to
succeed right now.
Alphasort the flags and doc how to get the updated list, this makes it
easy to compare and keep up to date.
This enables quite a few javac warnings from java11+ that weren't
enabled for some reason. None of them fail, so lock them in.
Additionally some newer checks are only recognized for newer JDK
versions, so they are only enabled based on the javac version used. They
will cause no annoyance because they relate to newer language features.
