Overriding a tool in flake-parts module requires `mkForce`

[Mango The Fourth]

Currently, I have to
settings.tools.fourmolu = lib.mkForce config.haskellProjects.default.outputs.finalPackages.fourmolu_0_13_1_0;

I would rather not use mkForce here, it would be nice if the toolset was defined with mkDefault in order to do so.

[Domen Kožar]

This is a good candidate for #196

[sander]

@MangoIV, you can now override individual packages without going through tools:

{
  hooks.fourmolu.package = config.haskellProjects.default.outputs.finalPackages.fourmolu_0_13_1_0;
}