feat: assign highlight groups in result window

[Skyppex]

currently the result window highlights seem to be locked as NonText for the row numbers and ascii box art stuff, and some sort of plain text for the column names and values. all i'm asking for here is that there is a candies property in the result config where i can put what highlights i want for each of these.

My proposed separation is this: allow highlight groups individually for:

• ascii box art
• column names
• row numbers
• cell values

with these 4 groups the output is highly configurable and will probably suffice for most people including myself.