refactor: cleanup shutdown hook registration method documentation

Signed-off-by: Chris Laprun <metacosm@gmail.com>

Author: metacosm

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/Operator.java

@@ -137,11 +137,22 @@ protected ConfigurationService initConfigurationService(
    * <p>Note that you might want to tune "terminationGracePeriodSeconds" for the Pod running the
    * controller.
    *
-   * @param gracefulShutdownTimeout timeout to wait for executor threads to complete actual
-   *     reconciliations
+   * @param gracefulShutdownTimeout ignored, configure {@link
+   *     ConfigurationService#reconciliationTerminationTimeout()} instead
+   * @deprecated Use {@link #installShutdownHook()} instead
    */
   @SuppressWarnings("unused")
+  @Deprecated(forRemoval = true)
   public void installShutdownHook(Duration gracefulShutdownTimeout) {
+    installShutdownHook();
+  }
+
+  /**
+   * Adds a shutdown hook that automatically calls {@link #stop()} when the app shuts down. Note
+   * that graceful shutdown is usually not needed, but some {@link Reconciler} implementations might
+   * require it.
+   */
+  public void installShutdownHook() {
     if (!leaderElectionManager.isLeaderElectionEnabled()) {
       Runtime.getRuntime().addShutdownHook(new Thread(this::stop));
     } else {
@@ -188,6 +199,10 @@ public synchronized void start() {
     }
   }
 
+  /**
+   * Gracefully shuts down the operator, using the timeout defined by {@link
+   * ConfigurationService#reconciliationTerminationTimeout()} to wait for reconciliations to finish.
+   */
   @Override
   public void stop() throws OperatorException {
     Duration reconciliationTerminationTimeout =