One-Up, One-Down -> Tip, Top

In [Building Skill With Feedback](https://carpentries.github.io/instructor-training/06-feedback/index.html) the "one up, one down" technique could be renamed to "one tip, one top".
"One up, one down" asks explicitly for a negative point that should be raised. A more interactive way would be to ask for improvement on such a point, e.g. giving a tip instead of "one-down". This way, the learners think of a solution to the problem already, by still pointing out things that did not work as they expected.
"One-up" would be called "top", respectively.
We used this kind of feedback system already with my instructor training. It is more like an expansion to the existing "one-up, one-down".

Open the linked “Building Skill With Feedback” lesson and locate the section describing the “one up, one down” technique. Review the proposed “one tip, one top” terminology and the accompanying explanation, then update the lesson so the new naming and expanded feedback approach are clear and consistent.

Written by the indexing model from the issue text.