Fix more javadoc errors

These worked with Java 21, but not with Java 11.

pmd-test/src/main/java/net/sourceforge/pmd/test/AbstractAntTestHelper.java

@@ -36,19 +36,17 @@ import com.github.stefanbirkner.systemlambda.SystemLambda;
  * <p>Usage template:
  *
  * <pre>
- * {@code
  * class MyPMDTaskTest extends AbstractAntTestHelper {
  *     MyPMDTaskTest() {
  *          antTestScriptFilename = "mypmdtasktest.xml";
  *     }
  *
- *     @Test
+ *     &#64;Test
  *     void myTest() {
  *         executeTarget("testMyTarget");
  *         assertOutputContaining("Expected Violation Message");
  *     }
  * }
- * }
  * </pre>
  *
  * @author Romain Pelisse &lt;belaran@gmail.com&gt;