Upgrade to GHC 9.4.8
A bit related to #304 (closed) because I built on top of the latest commit there.
Overall GHC 9.4.8 is better supported: e.g. with ghcup I have HLS already for GHC 9.4.8 while for GHC 9.4.7 I need to build a custom one.
And for GHC 9.4.7 HLS is at most at version 2.5.0.0 while for GHC 9.4.8 I can bump up to 2.9.0.1.
NOTE One thing I'm not sure of is darwin - @AlfredoDiNapoli could you check?