treewide: Format all Nix files

Format all Nix files using the officially approved formatter,
making the CI check introduced in the previous commit succeed:

  nix-build ci -A fmt.check

This is the next step of the of the [implementation](https://github.com/NixOS/nixfmt/issues/153)
of the accepted [RFC 166](https://github.com/NixOS/rfcs/pull/166).

This commit will lead to merge conflicts for a number of PRs,
up to an estimated ~1100 (~33%) among the PRs with activity in the past 2
months, but that should be lower than what it would be without the previous
[partial treewide format](https://github.com/NixOS/nixpkgs/pull/322537).

Merge conflicts caused by this commit can now automatically be resolved while rebasing using the
[auto-rebase script](8616af08d9/maintainers/scripts/auto-rebase).

If you run into any problems regarding any of this, please reach out to the
[formatting team](https://nixos.org/community/teams/formatting/) by
pinging @NixOS/nix-formatting.

nixos/lib/make-squashfs.nix

@@ -1,18 +1,22 @@
-{ lib, stdenv, squashfsTools, closureInfo
+{
+  lib,
+  stdenv,
+  squashfsTools,
+  closureInfo,
 
-,  fileName ? "squashfs"
-, # The root directory of the squashfs filesystem is filled with the
+  fileName ? "squashfs",
+  # The root directory of the squashfs filesystem is filled with the
   # closures of the Nix store paths listed here.
-  storeContents ? []
+  storeContents ? [ ],
   # Pseudo files to be added to squashfs image
-, pseudoFiles ? []
-, noStrip ? false
-, # Compression parameters.
+  pseudoFiles ? [ ],
+  noStrip ? false,
+  # Compression parameters.
   # For zstd compression you can use "zstd -Xcompression-level 6".
-  comp ? "xz -Xdict-size 100%"
-, # create hydra build product. will put image in directory instead
+  comp ? "xz -Xdict-size 100%",
+  # create hydra build product. will put image in directory instead
   # of directly in the store
-  hydraBuildProduct ? false
+  hydraBuildProduct ? false,
 }:
 
 let
@@ -34,24 +38,28 @@ stdenv.mkDerivation {
       cp $closureInfo/registration nix-path-registration
 
       imgPath="$out"
-    '' + lib.optionalString hydraBuildProduct ''
+    ''
+    + lib.optionalString hydraBuildProduct ''
 
       mkdir $out
       imgPath="$out/${fileName}.squashfs"
-    '' + lib.optionalString stdenv.buildPlatform.is32bit ''
+    ''
+    + lib.optionalString stdenv.buildPlatform.is32bit ''
 
       # 64 cores on i686 does not work
       # fails with FATAL ERROR: mangle2:: xz compress failed with error code 5
       if ((NIX_BUILD_CORES > 48)); then
         NIX_BUILD_CORES=48
       fi
-    '' + ''
+    ''
+    + ''
 
       # Generate the squashfs image.
       mksquashfs nix-path-registration $(cat $closureInfo/store-paths) $imgPath ${pseudoFilesArgs} \
         -no-hardlinks ${lib.optionalString noStrip "-no-strip"} -keep-as-directory -all-root -b 1048576 ${compFlag} \
         -processors $NIX_BUILD_CORES -root-mode 0755
-    '' + lib.optionalString hydraBuildProduct ''
+    ''
+    + lib.optionalString hydraBuildProduct ''
 
       mkdir -p $out/nix-support
       echo "file squashfs-image $out/${fileName}.squashfs" >> $out/nix-support/hydra-build-products