We currently have postBuild and notifications sections at the top level of pipeline. It is possible to send notifications in either of them. Notifications in postBuild are sent from a node while notifications within notifications are sent outside of a node. Some plugins like 'email-ext' must be within a node to work and will not work in the notifications section.
Within a stage we have only a post section but no notifications section. All notifications within a stage must be done in the post block.
This inconsistency between stage-level settings and top-level settings and support for different plugins creates unneeded complexity in trying to document best practices for usage.
We should either create a notifications section at the stage level or document how to do notifications with post and postBuild only.