comment for Javadoc System.properties

src/java/org/web3d/util/Xj3dVersionInformation.java

@@ -74,6 +74,7 @@ public class Xj3dVersionInformation {
 
     // https://docs.oracle.com/javase/tutorial/essential/environment/sysprop.html
     // https://stackoverflow.com/questions/5103121/how-to-find-the-jvm-version-from-a-program
+    // https://docs.oracle.com/en/java/javase/23/docs/api/java.base/java/lang/System.html#getProperties()
     public static final String OS_JAVA_VERSION_MESSAGE  = "   Operating system: " + System.getProperty("os.name") + SP + System.getProperty("os.version") + "\n" +
                                                           "   Java environment: " + System.getProperty("java.runtime.name") + SP + JAVA_VERSION;
     /**