[Option] Highlight single digit draft in cell line if this digit isn't be drafted in other cells

[Twilightssuperb]

Since Gauguin already have option to fill single cages at start, we can bring something like that for drafts. At hardest levels (9*9 with 1...9 digits) sometimes I fill almost all digits as drafts, I can't be concentrated all time, so I'm losing sight of obvious solutions — and find that some digit draft is single in whole cell line. Yes, there are many other digit drafts in this current cell (from 1 to 9), but special 2, e.g., is drafted only in one this cell.

I think this idea needs some simple script (that will search single digit drafts) and could be easy to implement it.

Sorry for clumsy talk. 🫠

It's not the same as in #64.