Fix documentation.

Author: smswz

README.md

@@ -114,7 +114,6 @@ class Example {
 
         Keyring legacyKeyring = AesWrapKeyring.builder()
                 .wrappingKey(aesKey)
-                .nonLegacyKeyring(keyring)
                 .build();
 
         MaterialsManager materialsManager = LegacyDecryptMaterialsManager.builder()

src/main/java/software/amazon/encryption/s3/legacy/materials/LegacyDecryptMaterialsManager.java

@@ -10,6 +10,10 @@
 
 /**
  * This class supports legacy decrypt as well as non-legacy encrypt and decrypt.
+ *
+ * It will only use the non-legacy keyring for encrypt.
+ * For decrypt, it will attempt to use the legacy keyring first.
+ * If the legacy keyring fails to decrypt, the non-legacy keyring will be used.
  */
 public class LegacyDecryptMaterialsManager implements MaterialsManager {
     private final Keyring _keyring;