Fix some errors in phpdocs.

Backported from 25cd430 (master).

lib/Predis/Client.php

@@ -202,7 +202,7 @@ class Client implements ClientInterface
     /**
      * Retrieves a single connection out of an aggregated connections instance.
      *
-     * @param  string                               $connectionId Index or alias of the connection.
+     * @param  string                               $connectionId Index or alias of the single connection.
      * @return Connection\SingleConnectionInterface
      */
     public function getConnectionById($connectionId)

lib/Predis/Collection/Iterator/CursorBasedIterator.php

@@ -60,8 +60,8 @@ abstract class CursorBasedIterator implements Iterator
      * command required to fetch elements from the server to perform
      * the iteration.
      *
-     * @param ClientInterface Client connected to Redis.
-     * @param string $commandID Command ID.
+     * @param ClientInterface $client    Client connected to Redis.
+     * @param string          $commandID Command ID.
      */
     protected function requiredCommand(ClientInterface $client, $commandID)
     {

lib/Predis/Collection/Iterator/ListKey.php

@@ -66,8 +66,8 @@ class ListKey implements Iterator
      * command required to fetch elements from the server to perform
      * the iteration.
      *
-     * @param ClientInterface Client connected to Redis.
-     * @param string $commandID Command ID.
+     * @param ClientInterface $client    Client connected to Redis.
+     * @param string          $commandID Command ID.
      */
     protected function requiredCommand(ClientInterface $client, $commandID)
     {

lib/Predis/Command/AbstractCommand.php

@@ -59,9 +59,7 @@ abstract class AbstractCommand implements CommandInterface
     }
 
     /**
-     * Gets the argument from the arguments list at the specified index.
-     *
-     * @param array $arguments Position of the argument.
+     * {@inheritdoc}
      */
     public function getArgument($index)
     {

lib/Predis/Command/RawCommand.php

@@ -44,6 +44,7 @@ class RawCommand implements CommandInterface
      *
      * @param string $commandID Redis command ID.
      * @param string ... Arguments list for the command.
+     * @return CommandInterface
      */
     public static function create($commandID /* [ $arg, ... */)
     {
@@ -87,9 +88,7 @@ class RawCommand implements CommandInterface
     }
 
     /**
-     * Gets the argument from the arguments list at the specified index.
-     *
-     * @param array $arguments Position of the argument.
+     * {@inheritdoc}
      */
     public function getArgument($index)
     {

lib/Predis/Connection/AbstractConnection.php

@@ -50,7 +50,8 @@ abstract class AbstractConnection implements SingleConnectionInterface
     /**
      * Checks some of the parameters used to initialize the connection.
      *
-     * @param ConnectionParametersInterface $parameters Parameters used to initialize the connection.
+     * @param  ConnectionParametersInterface $parameters Initialization parameters for the connection.
+     * @return ConnectionParametersInterface
      */
     protected function checkParameters(ConnectionParametersInterface $parameters)
     {

lib/Predis/Connection/ConnectionParameters.php

@@ -30,7 +30,7 @@ class ConnectionParameters implements ConnectionParametersInterface
     );
 
     /**
-     * @param string|array Connection parameters in the form of an URI string or a named array.
+     * @param string|array $parameters Connection parameters in the form of an URI string or a named array.
      */
     public function __construct($parameters = array())
     {