[ISSUE apache#4101] Fix Javadoc for ClientBuilder.keepAliveInterval

Fixes apache#4101 

### Motivation

fix issue

### Modifications

fix keepAliveInterval method java doc

pulsar-client-api/src/main/java/org/apache/pulsar/client/api/ClientBuilder.java

@@ -292,9 +292,9 @@ ClientBuilder authentication(String authPluginClassName, Map<String, String> aut
 
     /**
      * Set the interval between each stat info <i>(default: 60 seconds)</i> Stats will be activated with positive
-     * statsIntervalSeconds It should be set to at least 1 second
+     * statsInterval It should be set to at least 1 second
      *
-     * @param statsIntervalSeconds
+     * @param statsInterval
      *            the interval between each stat info
      * @param unit
      *            time unit for {@code statsInterval}
@@ -334,13 +334,13 @@ ClientBuilder authentication(String authPluginClassName, Map<String, String> aut
     ClientBuilder maxNumberOfRejectedRequestPerConnection(int maxNumberOfRejectedRequestPerConnection);
 
     /**
-     * Set keep alive interval in seconds for each client-broker-connection. <i>(default: 30)</i>.
+     * Set keep alive interval for each client-broker-connection. <i>(default: 30 seconds)</i>.
      *
-     * @param keepAliveIntervalSeconds
-     * @param unit time unit for {@code statsInterval}
+     * @param keepAliveInterval
+     * @param unit the time unit in which the keepAliveInterval is defined
      * @return the client builder instance
      */
-    ClientBuilder keepAliveInterval(int keepAliveIntervalSeconds, TimeUnit unit);
+    ClientBuilder keepAliveInterval(int keepAliveInterval, TimeUnit unit);
 
     /**
      * Set the duration of time to wait for a connection to a broker to be established. If the duration passes without a

pulsar-client/src/main/java/org/apache/pulsar/client/impl/ClientBuilderImpl.java

@@ -197,8 +197,8 @@ public ClientBuilder maxNumberOfRejectedRequestPerConnection(int maxNumberOfReje
     }
 
     @Override
-    public ClientBuilder keepAliveInterval(int keepAliveIntervalSeconds, TimeUnit unit) {
-        conf.setKeepAliveIntervalSeconds((int)unit.toSeconds(keepAliveIntervalSeconds));
+    public ClientBuilder keepAliveInterval(int keepAliveInterval, TimeUnit unit) {
+        conf.setKeepAliveIntervalSeconds((int)unit.toSeconds(keepAliveInterval));
         return this;
     }