* New "display_output" hook.
* Fix unrelated "clippy" complaint in nu-tables crate.
* Fix code-formattng and style issues in "display_output" hook
* Enhance eval_hook to return PipelineData.
This allows a hook (including display_output) to return a value.
Co-authored-by: JT <547158+jntrnr@users.noreply.github.com>