Fix reference to TcpTransport in documentation

Author: Tim-Brooks

core/src/test/java/org/elasticsearch/transport/TcpTransportTests.java

@@ -45,7 +45,7 @@
 
 import static org.hamcrest.Matchers.equalTo;
 
-/** Unit tests for TCPTransport */
+/** Unit tests for {@link TcpTransport} */
 public class TcpTransportTests extends ESTestCase {
 
     /** Test ipv4 host with a default port works */