Improve scatter documentation
The current documentation in the user guide has a "Scattering Workflows" section. In #222 we rename it to "Scattering Steps", and the content was described a scatter with workflow steps.
This issue is a follow-up to work on improvements for the scattering of workflows and steps. The existing description in the specification itself is great, and could be included/imported/improved/or used as reference: https://github.com/common-workflow-language/cwl-v1.2/blob/8c52930afd0fb4f474ae18d9ff76920d65bb4528/Workflow.yml#L496-L536
@Mackenzie-OO7 -- I think you mentioned working on this one. Some links for you:
(1) "real-world" but simple enough to use in guide example from still being written advanced tutorial: https://common-workflow-lab.github.io/cwl-intermediate-tutorial/scatter/index.html (2) description and simple examples of all the types of scatters: https://sage-workflows.readthedocs.io/en/latest/cwl_examples/cwl_scattering-inputs.html
I will look for some other "real-world" examples but I think this is enough for you to start with.