Add `fourmoluWithOpts`
We want to be able to call fourmolu with a custom list of -o arguments specifying the GHC options.
Example: https://github.com/Plutonomicon/plutarch/blob/aecc2050eb63ff0041576473aa3193070fe91314/bin/format#L5
Something like
fourmoluWithOpts = opts: lint-bin
"find . -name '*.hs' | xargs ${pkgs.haskellPackages.fourmolu}/bin/fourmolu -m inplace ${opts}";