Add design resources

[jlcohoon]

People using this lesson may benefit from some info on good design, especially advice that might help them prevent usability issues. Below are some thoughts on how to address the issue, but other contributors might have different ideas.

• Add one more episode to the lesson on "next steps" that includes design resources/advice
• Or add a collapsable div to the end of the "Analyzing data and reporting results" section
• Point users to the STRUDEL Design System
• List some best practices for design and accessibility, keeping in mind that the tool being evaluated might be a CLI, API, or docs (i.e. not a GUI)

Before addressing this issue, please leave a comment describing your approach so that others can assist without duplicating work. Tag a reviewer (e.g. @jlcohoon) as well.
Please check that the "Overview" and "Key Points" don't need adjusting after your edits

Carpentries info on formatting the different kinds of callouts and collapsable content like exercises might be useful: https://carpentries.github.io/sandpaper-docs/instructor/component-guide.html
https://carpentries.github.io/lesson-development-training/lesson-content.html#adding-exercises