Duplicate text between lesson material and slides

[DaniBodor]

We currently have a lof of duplicate text in the the lesson materials and slides. E.g. this PR copies a lot of the slide text into the materials. This will likely happen for most or all modules as well. We do want the same text in both places as the lesson materials do live separately from the slides. However, it is not ideal to have duplicate text in different places, as any future updates would require changing 2 different near-identical documents.

We should think of a way to streamline this. Potentially, we could try to come up with a solution where a single md document can be rendered in 2 different ways, either for slides or for materials. Alternatively, I recently ran into this package, that allows reading excerpts from one markdown file in another one.

[svenvanderburg]

My proposal:

• Slides are an integral part of our lesson material, on those parts where we introduce more theoretical concepts (i.e. no live coding or exercises).
• We link to the appropriate slides from the workbench lesson, with some guiding text like: 'In these slides we explain modular coding'. We can add instructor notes if necessary to guide instructors through the slides
• We should not have duplicate content in the workbench lesson that is already covered by slides

[DaniBodor]

Sounds like a good solution. It will be important for people who are migrating lesson content to be aware of this. Where can we place these guidelines to ensure they are visible?