Please, organize GHC 9.2 API changes

[Anton-Latukha]

GHC 9.2 still had API organization & changes.

During hard work in #2503 - some of CPP were placed around, #2503 (comment), the organization would be appreciated.

CPP is justified in .ExactPrint modules, since ghc-exactprint has been redesigned in ghc 9.2: the types and programming model are completely different, so much that it doesn't make sense to abstract those differences behind Compat modules.

The rest need to be organized into Compat infrastructure. ghcide's GHC.Compat infrastructure is planned for #2454, so it is a community-useful work.

[pepeiborra]

During hard work in #2503 - the 9.2 CPP organization was sacrificed for the main agenda & CPPs were scattered across the codebase. #2503 (comment)

This is not completely accurate - ghc-exactprint has been redesigned in ghc 9.2 and the types and programming model are completely different, so much that it doesn't make sense to abstract the differences behind Compat modules. So CPP is justified in .ExactPrint modules. That said, it may be possible to tidy some things up in order to reduce the amount of CPP.

[Anton-Latukha]

In cases like these I love to use the rewriting paradigm, I just allow editing my headposts to clarify/add details. I do it myself to add details to reports headposts. And I often open reports to properly kanban "Next: " tasks regardless of my understanding & the source they came from, so frequently I await for context to be modified a bit & details to be added.

(updated the headpost with information)

[michaelpj]

Refactoring our CPP would be nice, but this particular thing is not going to get done