[isabelle-dev] Towards Isabelle2024-RC1

[Makarius]

Dear Isabelle contributors,

we have approx. 10 days left until Isabelle2024-RC1. That is the first public 
release candidate, and there is usually time until RC2/RC3 to finalize 
everything. See also 
https://isabelle-dev.sketis.net/phame/post/view/76/release_candidates_for_isabelle2024

Now is a good point to update CONTRIBUTORS and NEWS: the headline says 
"Isabelle NEWS -- history of user-relevant changes", or seen from a different 
angle: a change that is not user-relevant is hardly relevant at all.


	Makarius