Add java-doc for implemented methods of io.netty.util.concurrent.Future#cancel(boolean mayInterruptIfRunning)

Motivation:

The methods implement io.netty.util.concurrent.Future#cancel(boolean mayInterruptIfRunning) which actually ignored the param mayInterruptIfRunning.We need to add comments for the `mayInterruptIfRunning` param.

Modifications:

Add comments for the `mayInterruptIfRunning` param.

Result:

People who call the `cancel` method will be more clear about the effect of `mayInterruptIfRunning` param.

common/src/main/java/io/netty/util/concurrent/CompleteFuture.java

@@ -140,6 +140,11 @@ public abstract class CompleteFuture<V> extends AbstractFuture<V> {
         return false;
     }
 
+    /**
+     * {@inheritDoc}
+     *
+     * @param mayInterruptIfRunning this value has no effect in this implementation.
+     */
     @Override
     public boolean cancel(boolean mayInterruptIfRunning) {
         return false;

common/src/main/java/io/netty/util/concurrent/DefaultPromise.java

@@ -308,6 +308,11 @@ public class DefaultPromise<V> extends AbstractFuture<V> implements Promise<V> {
         return (V) result;
     }
 
+    /**
+     * {@inheritDoc}
+     *
+     * @param mayInterruptIfRunning this value has no effect in this implementation.
+     */
     @Override
     public boolean cancel(boolean mayInterruptIfRunning) {
         if (RESULT_UPDATER.compareAndSet(this, null, CANCELLATION_CAUSE_HOLDER)) {

common/src/main/java/io/netty/util/concurrent/ScheduledFutureTask.java

@@ -146,6 +146,11 @@ final class ScheduledFutureTask<V> extends PromiseTask<V> implements ScheduledFu
         }
     }
 
+    /**
+     * {@inheritDoc}
+     *
+     * @param mayInterruptIfRunning this value has no effect in this implementation.
+     */
     @Override
     public boolean cancel(boolean mayInterruptIfRunning) {
         boolean canceled = super.cancel(mayInterruptIfRunning);

transport/src/main/java/io/netty/channel/VoidChannelPromise.java

@@ -164,6 +164,11 @@ final class VoidChannelPromise extends AbstractFuture<Void> implements ChannelPr
         return false;
     }
 
+    /**
+     * {@inheritDoc}
+     *
+     * @param mayInterruptIfRunning this value has no effect in this implementation.
+     */
     @Override
     public boolean cancel(boolean mayInterruptIfRunning) {
         return false;