Javadoc fixes. (#1217)

* Javadoc fixes.

* Oopsie.
diff --git a/common/src/main/java/org/conscrypt/ArrayUtils.java b/common/src/main/java/org/conscrypt/ArrayUtils.java
index 981f5ad..d946713 100644
--- a/common/src/main/java/org/conscrypt/ArrayUtils.java
+++ b/common/src/main/java/org/conscrypt/ArrayUtils.java
@@ -21,6 +21,7 @@
 /**
  * Compatibility utility for Arrays.
  */
+@Internal
 public final class ArrayUtils {
     private ArrayUtils() {}
 
diff --git a/common/src/main/java/org/conscrypt/Hkdf.java b/common/src/main/java/org/conscrypt/Hkdf.java
index e18b36c..d5668d2 100644
--- a/common/src/main/java/org/conscrypt/Hkdf.java
+++ b/common/src/main/java/org/conscrypt/Hkdf.java
@@ -29,7 +29,7 @@
  * Instances should be instantiated using the standard JCA name for the required HMAC.
  * <p>
  * Each invocation of expand or extract uses a new Mac instance and so instances
- * of Hkdf are thread-safe.
+ * of Hkdf are thread-safe.</p>
  */
 public final class Hkdf {
     // HMAC algorithm to use.
diff --git a/common/src/main/java/org/conscrypt/HpkeContext.java b/common/src/main/java/org/conscrypt/HpkeContext.java
index 4317796..355997f 100644
--- a/common/src/main/java/org/conscrypt/HpkeContext.java
+++ b/common/src/main/java/org/conscrypt/HpkeContext.java
@@ -23,8 +23,6 @@
 
 /**
  * Hybrid Public Key Encryption (HPKE) sender APIs.
- *
- * @see <a href="https://www.rfc-editor.org/rfc/rfc9180.html#hpke-export">HPKE RFC 9180</a>
  * <p>
  * Base class for HPKE sender and recipient contexts.
  * <p>
@@ -36,6 +34,7 @@
  * to use for seal and open operations.
  *
  * Secret key material based on the context may also be generated and exported as per RFC 9180.
+ * @see <a href="https://www.rfc-editor.org/rfc/rfc9180.html#hpke-export">RFC 9180 (HPKE)</a>
  */
 public abstract class HpkeContext {
   protected final HpkeSpi spi;
diff --git a/common/src/main/java/org/conscrypt/HpkeImpl.java b/common/src/main/java/org/conscrypt/HpkeImpl.java
index a09f3df..3c62611 100644
--- a/common/src/main/java/org/conscrypt/HpkeImpl.java
+++ b/common/src/main/java/org/conscrypt/HpkeImpl.java
@@ -34,6 +34,7 @@
  * Implementation of {@link HpkeSpi}.  Should not be used directly, but rather by one
  * of the subclasses of {@link HpkeContext}.
  */
+@Internal
 public class HpkeImpl implements HpkeSpi {
   private final HpkeSuite hpkeSuite;
 
diff --git a/common/src/main/java/org/conscrypt/XdhKeySpec.java b/common/src/main/java/org/conscrypt/XdhKeySpec.java
index 9848ae7..c24ac11 100644
--- a/common/src/main/java/org/conscrypt/XdhKeySpec.java
+++ b/common/src/main/java/org/conscrypt/XdhKeySpec.java
@@ -6,7 +6,7 @@
 
 /**
  * External Diffie–Hellman key spec holding a key which could be either a public or private key.
- *
+ * <p>
  * Subclasses {@code EncodedKeySpec} using the non-Standard "raw" format.  The XdhKeyFactory
  * class utilises this in order to create XDH keys from raw bytes and to return them
  * as an XdhKeySpec allowing the raw key material to be extracted from an XDH key.
@@ -40,8 +40,7 @@
     if (this == o) return true;
     if (!(o instanceof EncodedKeySpec)) return false;
     EncodedKeySpec that = (EncodedKeySpec) o;
-    return (getFormat().equals(that.getFormat())
-        && (Arrays.equals(getEncoded(), that.getEncoded())));
+    return (getFormat().equals(that.getFormat()) && Arrays.equals(getEncoded(), that.getEncoded()));
   }
 
   @Override