Add default value to options in LifecycleNode construnctor. Update AP…

…I documentation. (#775)

Signed-off-by: Esteve Fernandez <esteve@apache.org>

rclcpp_lifecycle/include/rclcpp_lifecycle/lifecycle_node.hpp

@@ -115,14 +115,13 @@ class LifecycleNode : public node_interfaces::LifecycleNodeInterface,
   /**
    * \param[in] node_name Name of the node.
    * \param[in] namespace_ Namespace of the node.
-   * \param[in] context The context for the node (usually represents the state of a process).
    * \param[in] options Additional options to control creation of the node.
    */
   RCLCPP_LIFECYCLE_PUBLIC
   LifecycleNode(
     const std::string & node_name,
     const std::string & namespace_,
-    const rclcpp::NodeOptions & options);
+    const rclcpp::NodeOptions & options = rclcpp::NodeOptions());
 
   RCLCPP_LIFECYCLE_PUBLIC
   virtual ~LifecycleNode();