[ci skip] DocBlocks for DB drivers' result classes

Partially fixes issue #1295.
diff --git a/system/database/drivers/mysql/mysql_result.php b/system/database/drivers/mysql/mysql_result.php
index 67ee06e..4bfa0ae 100644
--- a/system/database/drivers/mysql/mysql_result.php
+++ b/system/database/drivers/mysql/mysql_result.php
@@ -39,9 +39,9 @@
 class CI_DB_mysql_result extends CI_DB_result {
 
 	/**
-	 * Constructor
+	 * Class constructor
 	 *
-	 * @param	object
+	 * @param	object	&$driver_object
 	 * @return	void
 	 */
 	public function __construct(&$driver_object)
@@ -145,9 +145,9 @@
 	 *
 	 * Moves the internal pointer to the desired offset. We call
 	 * this internally before fetching results to make sure the
-	 * result set starts at zero
+	 * result set starts at zero.
 	 *
-	 * @param	int	$n = 0
+	 * @param	int	$n
 	 * @return	bool
 	 */
 	protected function _data_seek($n = 0)
@@ -178,7 +178,7 @@
 	 *
 	 * Returns the result set as an object
 	 *
-	 * @param	string
+	 * @param	string	$class_name
 	 * @return	object
 	 */
 	protected function _fetch_object($class_name = 'stdClass')