Enable Java 25 support (#11148)

* Bump winstone to get Jetty 12.1.1

* Accept to start Jenkins with Java 25

* Build with Java 25

* Remove inaccurate javadoc that includes an incorrect link

The Javadoc comment said:

> When executing the resulting Callable, it executes
> FileCallable#act(FileCallable) on this FilePath.

The FileCallable interface does not have an `act(FileCallable)` method.
That absence causes the Javadoc generation to fail on Java 25.

There is a `FilePath.act(FileCallable)` method that could be inserted
instead, but I'm not confident the comment would then be correct.

Testing done:

Confirmed that Javadoc generation fails on Java 25 without this change.

Confirmed that Javadoc generation passes on Java 25 with this change.

(cherry picked from commit 3fdf9c18db)

* Temporary fix for javadoc build

* Bump winstone to 8.14

* Update Jenkinsfile

---------

Co-authored-by: Bruno Verachten <gounthar@gmail.com>
Co-authored-by: Mark Waite <mark.earl.waite@gmail.com>
Co-authored-by: Tim Jacomb <21194782+timja@users.noreply.github.com>

war/src/main/java/executable/Main.java

@@ -76,7 +76,7 @@ public class Main {
      * This list must remain synchronized with the one in {@code
      * JavaVersionRecommendationAdminMonitor}.
      */
-    private static final NavigableSet<Integer> SUPPORTED_JAVA_VERSIONS = new TreeSet<>(List.of(17, 21));
+    private static final NavigableSet<Integer> SUPPORTED_JAVA_VERSIONS = new TreeSet<>(List.of(17, 21, 25));
 
     /**
      * Sets custom session cookie name.