Identify person as "Carpentries Instructor" (not lesson program specific)

In a testimonial in the [The Importance of Going Slowly](https://carpentries.github.io/instructor-training/02-practice-learning.html#the-importance-of-going-slowly), the testimonial is attributed to a "SWC Instructor." This may be a holdover from long ago when we had lesson program specific Instructor badges. Should this be changed to say "Carpentries Instructor" instead?

Open the testimonial in 02-practice-learning.md at the “The Importance of Going Slowly” section and review the surrounding wording. Change the attribution from “SWC Instructor” to “Carpentries Instructor” if consistent with the current terminology, then check the rendered lesson to confirm the testimonial displays correctly.

Written by the indexing model from the issue text.