Clarify differences between `FAILURE` and `ERROR` for `CallbackReturn`

[solonovamax]

Description

The differences between the FAILURE and ERROR return codes should be clarified in the documentation (design document, demos, code documentation, etc.)

Motivation

I'm unclear on the differences between rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn::FAILURE and rclcpp_lifecycle::node_interfaces::LifecycleNodeInterface::CallbackReturn::ERROR, and I think it would be very useful to clarify how exactly the two are different.
when should one be used instead of the other, etc.

Design / Implementation Considerations

No response

Additional Information

No response

[fujitatomoya]

https://github.com/ros2/rcl_interfaces/blob/79a773f9fb02dee0de23fb1b08ca4d187b313849/lifecycle_msgs/msg/Transition.msg#L71-L84, does this clarify your question? if not, please feel free to open the PR to add more description.

[solonovamax]

https://github.com/ros2/rcl_interfaces/blob/79a773f9fb02dee0de23fb1b08ca4d187b313849/lifecycle_msgs/msg/Transition.msg#L71-L84, does this clarify your question? if not, please feel free to open the PR to add more description.

yeah, I think this description is fine

it should be added as code documentation & to any relevant tutorials

[shlokbandiwar]

Hi, I’d like to work on this issue. Could you assign it to me?