MINOR: Fix few typos in the javadocs/docs

clients/src/main/java/org/apache/kafka/common/network/SslChannelBuilder.java

@@ -50,7 +50,7 @@ public class SslChannelBuilder implements ChannelBuilder, ListenerReconfigurable
     private SslPrincipalMapper sslPrincipalMapper;
 
     /**
-     * Constructs a SSL channel builder. ListenerName is provided only
+     * Constructs an SSL channel builder. ListenerName is provided only
      * for server channel builder and will be null for client channel builder.
      */
     public SslChannelBuilder(Mode mode, ListenerName listenerName, boolean isInterBrokerListener) {

clients/src/main/java/org/apache/kafka/common/network/SslTransportLayer.java

@@ -152,7 +152,7 @@ public class SslTransportLayer implements TransportLayer {
 
 
     /**
-    * Sends a SSL close message and closes socketChannel.
+    * Sends an SSL close message and closes socketChannel.
     */
     @Override
     public void close() throws IOException {
@@ -737,7 +737,7 @@ public class SslTransportLayer implements TransportLayer {
     }
 
     /**
-     * returns a SSL Session after the handshake is established
+     * returns an SSL Session after the handshake is established
      * throws IllegalStateException if the handshake is not established
      */
     public SSLSession sslSession() throws IllegalStateException {

clients/src/main/java/org/apache/kafka/common/network/TransportLayer.java

@@ -81,7 +81,7 @@ public interface TransportLayer extends ScatteringByteChannel, GatheringByteChan
     boolean hasPendingWrites();
 
     /**
-     * Returns `SSLSession.getPeerPrincipal()` if this is a SslTransportLayer and there is an authenticated peer,
+     * Returns `SSLSession.getPeerPrincipal()` if this is an SslTransportLayer and there is an authenticated peer,
      * `KafkaPrincipal.ANONYMOUS` is returned otherwise.
      */
     Principal peerPrincipal() throws IOException;

core/src/main/scala/kafka/server/KafkaApis.scala

@@ -1600,7 +1600,7 @@ class KafkaApis(val requestChannel: RequestChannel,
   def handleApiVersionsRequest(request: RequestChannel.Request): Unit = {
     // Note that broker returns its full list of supported ApiKeys and versions regardless of current
     // authentication state (e.g., before SASL authentication on an SASL listener, do note that no
-    // Kafka protocol requests may take place on a SSL listener before the SSL handshake is finished).
+    // Kafka protocol requests may take place on an SSL listener before the SSL handshake is finished).
     // If this is considered to leak information about the broker version a workaround is to use SSL
     // with client authentication which is performed at an earlier stage of the connection where the
     // ApiVersionRequest is not available.

docs/protocol.html

@@ -130,7 +130,7 @@
         this happens after SSL connection has been established.</li>
     <li>On receiving <code>ApiVersionsRequest</code>, a broker returns its full list of supported ApiKeys and
         versions regardless of current authentication state (e.g., before SASL authentication on an SASL listener, do note that no
-        Kafka protocol requests may take place on a SSL listener before the SSL handshake is finished). If this is considered to
+        Kafka protocol requests may take place on an SSL listener before the SSL handshake is finished). If this is considered to
         leak information about the broker version a workaround is to use SSL with client authentication which is performed at an
         earlier stage of the connection where the <code>ApiVersionRequest</code> is not available. Also, note that broker versions older
         than 0.10.0.0 do not support this API and will either ignore the request or close connection in response to the request.</li>

docs/security.html

@@ -1755,7 +1755,7 @@
 
         When performing an incremental bounce stop the brokers cleanly via a SIGTERM. It's also good practice to wait for restarted replicas to return to the ISR list before moving onto the next node.
         <p></p>
-        As an example, say we wish to encrypt both broker-client and broker-broker communication with SSL. In the first incremental bounce, a SSL port is opened on each node:
+        As an example, say we wish to encrypt both broker-client and broker-broker communication with SSL. In the first incremental bounce, an SSL port is opened on each node:
             <pre>
             listeners=PLAINTEXT://broker1:9091,SSL://broker1:9092
             </pre>