"Topical listing" is alphabetical, not by topic

[rhiaro]

The "Topical listing" of advance reading papers is not actually sorted by topic. This makes the instructions slightly confusing for adding things to the index.

@elenachachkarova - I can have a go at sorting these unless you prefer to?

[elenachachkarova]

@rhiaro, yes thank you, that would be very helpful, I think @ChristopherA said he might have a look as well.