I am having a hard time identifying the rules around this syntax, I see it and kind of understand it, but would like to find the documentation. I'm not sure how to google it though.
match (g:Group)<-[*1..2]-(s)
^^^^
^^^^ I would like to know more about this rule that limits path length
I understand that the above says "I only want to find paths that are between 1 and 2 edge traversals long", and it it really is that simple that's great; but I as I understand it the use of a star makes it a wildcard on which edges it can follow, while [:EdgeTypeIWant1..2] doesn't appear to be correct syntax. I probably have other questions as well that proper documentation (if I could find it) would be helpful with.
They are called variable length patterns.
The star is only an indicator that you're specifying a pattern of variable length, it's not a wildcard.
Your syntax would be: [:EdgeTypeIWant*1..2]