round out local Makefile checks

[geekosaur]

by collecting them and adding hlint. Other checks will follow, e.g. API checking once that lands.

Some other things might be added here later, and might lead to revision of various CI jobs. Consider this a start on addressing #10263 properly.

Template B: This PR does not modify behaviour or interface

E.g. the PR only touches documentation or tests, does refactorings, etc.

Include the following checklist in your PR:

• Patches conform to the coding conventions.
• Is this a PR that fixes CI? If so, it will need to be backported to older cabal release branches (ask maintainers for directions).

[geekosaur]

I did a once-over of the "quick checks", which are currently not covered; most of those, however, either require a pristine CI-like build environment (or docker) or require unreasonable dependencies (e.g. Sphinx). The one exception is the doctests, which I'm on the fence about.

There's also a question of how best to deal with fourmolu, considering that we require 0.12 and using 0.14 will cause failures either locally or in CI.

[mpickering]

Thanks @geekosaur :)

[geekosaur]

Once again merged as soon as "Validate Skip / Validate post job" went green and the other branch protection rules were satisfied (mostly this means "Quick checks", which despite the name take 7-10 minutes).