Switching to Fourmolu 0.14

Now that Fourmolu has integrated the Cabal codebase as a regression test (for which we are very grateful), let's examine what would change if we switched to 0.14: https://github.com/fourmolu/fourmolu/blob/main/compat-tests/cabal.diff

Question 1 (for cabal devs): Is this acceptable to us?

Question 2 (for Fourmolu devs): Are you willing to ask and receive help to provide the next versions of fourmolu with flags to deactivate arbitrary changes from Ormolu?

cc @brandonchinn178

Start by reviewing the linked Fourmolu compat-tests/cabal.diff and the Cabal regression-test setup. Compare the proposed Fourmolu 0.14 formatting changes with the project’s accepted style, then resolve whether the changes are acceptable and whether configurable Ormolu changes are needed. Done means the project has a decided migration path and any required follow-up is clearly scoped.

Written by the indexing model from the issue text.