Why it works: Link each section in 3.1 to the section it relates to in the getting started w/ how

[seabbs]

See title

[seabbs]

@SamuelBrand1 what do you think? Target at the same time as #72 ?

[SamuelBrand1]

Yeah good shout!

[SamuelBrand1]

This is a v good issue.

Extra detail: in f2f conversation with @seabbs we've discussed how the approach in the "why it works" vignette is different to underlying approach implemented in primarycensoreddist, and @parksw3 long paper.

In one sense this is good, because they should all be mathematically equivalent, therefore its a handy check and different perspectives on the same problem is good.

On the other hand, it creates a lot of potential confusion if we don't link carefully between ideas/approaches. This issue should aim to make those links.

[parksw3]

I think the math I put down here "proves" the equivalence in case it's useful...: #83