Support GHC 9.8, drop GHC 9.2

[langston-barrett]

No description provided.

[RyanGlScott]

The test suite likely won't compile without first resolving kquick/kvitable#2.

[langston-barrett]

Hmm, it looks like the diagnostics in that issue only consist of warnings, perhaps we can just bump the base bound and ignore the warnings until a more satisfying resolution is found?

[kquick]

The nix-ci.yml also needs to be updated to add GHC 9.8, which will necessitate flake.nix changes (essentially you can duplicate the changes in kquick/kvitable@4b4043b).

[langston-barrett]

At b85a510#r139131670, @kquick said:

What do you think of leaving the older GHC's, but marking them (via comment) as "optimistic builds; no longer supported"? My thinking here is that (a) unlike using regular ubuntu packages, the locking provided by flakes makes it easy to access these older versions, (b) these builds are pretty fast and lowe cost, and (c) this can let us explicitly know when our trailing horizon is updated.

I don't have a strong stance here, if we do go forward with this we should update doc/development.md and the README to reflect the new policy.

[kquick]

We wouldn't need to change the docs because we would still have the same policy of committing to support the recent 3-version window. This would just be adding the older GHC builds into the nix ci to inform us regarding the trailing support horizon.