Transition into discusion of badging

### How could the content be improved?

There is no transition to discussion of badging in the Getting Started on Instructor Certification episode. I believe this is the first discussion of badging in the training, and I don't think it's mentioned in the email that goes out to learners before training, so it might be unclear to learners what this badge refers to. They might wonder if it's a LinkedIn badge or a GitHub badge.

Would it be worth adding a brief explanation of badging either here before the list or somewhere earlier in the episode or lesson?

### Which part of the content does your suggestion apply to?

https://carpentries.github.io/instructor-training/instructor/14-checkout.html#what-does-a-badge-mean

Start in instructor/14-checkout.html at the “What does a badge mean?” section, then read the surrounding lesson content and the linked discussion point. Add a brief explanation that clarifies what the badge refers to and how it relates to instructor training, then verify the transition is clear for learners.

Written by the indexing model from the issue text.