Editor guidelines for code examples

[jmuheim]

TODO: create or add to GUIDELINES.md!

At the time being, code examples are working well, but their code is very inconsistent (and can probably be improved a lot).

Some day, it would be nice to refactor all examples to consistent, high-quality code. We need to decide e.g. whether to use a library like jQuery, or plain VanillaJS, what indention (space vs. tab), etc.

Questions:

• Should code examples be copy&pasted into real projects, or should they only be here as inspiration and proof of concept?
• Whenever a code is changed, it needs to be re-validated by A4a! This needs quite some effort, but needs to be done every now and then anyways.

[jmuheim]

The idea of adding videos to the ADG could help a lot with re-validating code examples: having a video showing a code example would document very thoroughly how it must behave. With this reference, even a screen reader beginner would be able to re-validate something.