Format .nix files

This does not include any automation for the release branch, but
is based on the configuration of https://github.com/NixOS/nix/pull/12349

    pre-commit run -a nixfmt-rfc-style

scripts/binary-tarball.nix

@@ -1,14 +1,18 @@
-{ runCommand
-, system
-, buildPackages
-, cacert
-, nix
+{
+  runCommand,
+  system,
+  buildPackages,
+  cacert,
+  nix,
 }:
 
 let
 
   installerClosureInfo = buildPackages.closureInfo {
-    rootPaths = [ nix cacert ];
+    rootPaths = [
+      nix
+      cacert
+    ];
   };
 
   inherit (nix) version;

scripts/installer.nix

@@ -1,36 +1,42 @@
-{ lib
-, runCommand
-, nix
-, tarballs
+{
+  lib,
+  runCommand,
+  nix,
+  tarballs,
 }:
 
-runCommand "installer-script" {
-  buildInputs = [ nix ];
-} ''
-  mkdir -p $out/nix-support
-
-  # Converts /nix/store/50p3qk8k...-nix-2.4pre20201102_550e11f/bin/nix to 50p3qk8k.../bin/nix.
-  tarballPath() {
-    # Remove the store prefix
-    local path=''${1#${builtins.storeDir}/}
-    # Get the path relative to the derivation root
-    local rest=''${path#*/}
-    # Get the derivation hash
-    local drvHash=''${path%%-*}
-    echo "$drvHash/$rest"
+runCommand "installer-script"
+  {
+    buildInputs = [ nix ];
   }
+  ''
+    mkdir -p $out/nix-support
 
-  substitute ${./install.in} $out/install \
-    ${lib.concatMapStrings
-      (tarball: let
-          inherit (tarball.stdenv.hostPlatform) system;
-        in '' \
-        --replace '@tarballHash_${system}@' $(nix --experimental-features nix-command hash-file --base16 --type sha256 ${tarball}/*.tar.xz) \
-        --replace '@tarballPath_${system}@' $(tarballPath ${tarball}/*.tar.xz) \
-        ''
-      )
-      tarballs
-    } --replace '@nixVersion@' ${nix.version}
+    # Converts /nix/store/50p3qk8k...-nix-2.4pre20201102_550e11f/bin/nix to 50p3qk8k.../bin/nix.
+    tarballPath() {
+      # Remove the store prefix
+      local path=''${1#${builtins.storeDir}/}
+      # Get the path relative to the derivation root
+      local rest=''${path#*/}
+      # Get the derivation hash
+      local drvHash=''${path%%-*}
+      echo "$drvHash/$rest"
+    }
 
-  echo "file installer $out/install" >> $out/nix-support/hydra-build-products
-''
+    substitute ${./install.in} $out/install \
+      ${
+        lib.concatMapStrings (
+          tarball:
+          let
+            inherit (tarball.stdenv.hostPlatform) system;
+          in
+          ''
+            \
+                   --replace '@tarballHash_${system}@' $(nix --experimental-features nix-command hash-file --base16 --type sha256 ${tarball}/*.tar.xz) \
+                   --replace '@tarballPath_${system}@' $(tarballPath ${tarball}/*.tar.xz) \
+          ''
+        ) tarballs
+      } --replace '@nixVersion@' ${nix.version}
+
+    echo "file installer $out/install" >> $out/nix-support/hydra-build-products
+  ''