connection numbered icons

[alixander]

now that #12 is in, this will be a pretty common use case. it would be ridiculous to have to find icons for each number.

we should make it more convenient. Maybe like

a -> b: Mix soil {
  icon: 1
}
b -> c: Plant seed {
  icon: 2
}

And the fill and stroke of the icon just depends on the theme

[bo-ku-ra]

avoid similarity to "--force-appendix".

[alixander]

Hadn't thought of that! As always, I appreciate the perspective you bring @bo-ku-ra