Stuck Detection and Highlight for Ishido

[hajo4]

It looks like Ishido has no stuck-detection, so
it would be nice to have assist highlight all allowed grid-positions
for the current tile.

[joeraz]

The hint logic for Ishido was added after the 3.0 release, so it, along with stuck detection, will be enabled in 3.1.

I'd have to look into what would need to be done for the highlight piles feature to work in Ishido.

[joeraz]

(Updated the title to disambiguate with an identically named issue)

[joeraz]

Looks like the current highlight logic is designed to highlight cards, not empty stacks. This will be trickier than I originally thought.

[hajo4]

have assist highlight all allowed grid-positions

Maybe paint green dots at those grid-positions, or a small/fake card-backside.