MINOR: Fix incomplete Javadoc comments in storage module

storage/src/main/java/org/apache/kafka/server/log/remote/metadata/storage/ProducerManager.java

@@ -57,7 +57,7 @@ public ProducerManager(TopicBasedRemoteLogMetadataManagerConfig rlmmConfig,
      * is considered complete.
      *
      * @param remoteLogMetadata RemoteLogMetadata to be published
-     * @return
+     * @return CompletableFuture that completes with RecordMetadata when the message is successfully published
      */
     CompletableFuture<RecordMetadata> publishMessage(RemoteLogMetadata remoteLogMetadata) {
         CompletableFuture<RecordMetadata> future = new CompletableFuture<>();

storage/src/main/java/org/apache/kafka/server/log/remote/metadata/storage/RemoteLogMetadataCache.java

@@ -276,7 +276,7 @@ private static long highestOffsetForEpoch(Integer leaderEpoch, RemoteLogSegmentM
     /**
      * Returns all the segments stored in this cache.
      *
-     * @return
+     * @return Iterator over all RemoteLogSegmentMetadata instances in the cache
      */
     Iterator<RemoteLogSegmentMetadata> listAllRemoteLogSegments() {
         // Return all the segments including unreferenced metadata.

storage/src/main/java/org/apache/kafka/storage/internals/log/LogDirFailureChannel.java

@@ -69,7 +69,7 @@ public void maybeAddOfflineLogDir(String logDir, String msg, IOException e) {
      * The method will wait if necessary until a new offline log directory becomes available
      * 
      * @return The next offline log dir.
-     * @throws InterruptedException
+     * @throws InterruptedException if the current thread is interrupted while waiting
      */
     public String takeNextOfflineLogDir() throws InterruptedException {
         return offlineLogDirQueue.take();