Change scatter/gather example to use better names

And add color coding, to make more clear what is a keyword and what is user provided

Locate the scatter/gather example in the workshop materials and review how keywords and user-provided names are currently presented. Update the example with clearer names and color coding that distinguishes those two categories; it is done when the example is easier to read and the distinction is visually consistent.

Written by the indexing model from the issue text.