[fix][doc] Fix typos in doc for MessageCryptoBc class (apache#21403)

pulsar-client-messagecrypto-bc/src/main/java/org/apache/pulsar/client/impl/crypto/MessageCryptoBc.java

@@ -564,7 +564,7 @@ private boolean getKeyAndDecryptData(MessageMetadata msgMetadata, ByteBuffer pay
             if (storedSecretKey != null) {
 
                 // Taking a small performance hit here if the hash collides. When it
-                // retruns a different key, decryption fails. At this point, we would
+                // returns a different key, decryption fails. At this point, we would
                 // call decryptDataKey to refresh the cache and come here again to decrypt.
                 if (decryptData(storedSecretKey, msgMetadata, payload, targetBuffer)) {
                     // If decryption succeeded, we can already return