sample: List after in has no indentation

[ParetoOptimalDev]

Input

{ pkgs ? import <nixpkgs> { overlays = [
    (import (builtins.fetchGit {
      url = "https://github.com/nix-community/emacs-overlay.git";
      ref = "master";
      rev = "37b7e04514d9f867d5a16b66ed112be6b674ddcb";
    }))
  ];
 }
}:
let
  myEmacs = pkgs.emacsGcc;
  emacsWithPackages = (pkgs.emacsPackagesNgGen myEmacs).emacsWithPackages;
in emacsWithPackages (epkgs:
                                              [ epkgs.melpaPackages.haskell-mode ])

Output

{ pkgs ? import <nixpkgs> {
    overlays = [
      (import (builtins.fetchGit {
        url = "https://github.com/nix-community/emacs-overlay.git";
        ref = "master";
        rev = "37b7e04514d9f867d5a16b66ed112be6b674ddcb";
      }))
    ];
  }
}:
let
  myEmacs = pkgs.emacsGcc;
  emacsWithPackages = (pkgs.emacsPackagesNgGen myEmacs).emacsWithPackages;
in
emacsWithPackages (epkgs:
[ epkgs.melpaPackages.haskell-mode ])

Desired output

{ pkgs ? import <nixpkgs> {
    overlays = [
      (import (builtins.fetchGit {
        url = "https://github.com/nix-community/emacs-overlay.git";
        ref = "master";
        rev = "37b7e04514d9f867d5a16b66ed112be6b674ddcb";
      }))
    ];
  }
}:
let
  myEmacs = pkgs.emacsGcc;
  emacsWithPackages = (pkgs.emacsPackagesNgGen myEmacs).emacsWithPackages;
in
emacsWithPackages (epkgs:
    [ epkgs.melpaPackages.haskell-mode ])

Or simply:

emacsWithPackages (epkgs:
- [ epkgs.melpaPackages.haskell-mode ])
+    [ epkgs.melpaPackages.haskell-mode ])