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

src/libcmd/package.nix

@@ -1,32 +1,33 @@
-{ lib
-, stdenv
-, mkMesonLibrary
+{
+  lib,
+  stdenv,
+  mkMesonLibrary,
 
-, nix-util
-, nix-store
-, nix-fetchers
-, nix-expr
-, nix-flake
-, nix-main
-, editline
-, readline
-, lowdown
-, nlohmann_json
+  nix-util,
+  nix-store,
+  nix-fetchers,
+  nix-expr,
+  nix-flake,
+  nix-main,
+  editline,
+  readline,
+  lowdown,
+  nlohmann_json,
 
-# Configuration Options
+  # Configuration Options
 
-, version
+  version,
 
-# Whether to enable Markdown rendering in the Nix binary.
-, enableMarkdown ? !stdenv.hostPlatform.isWindows
+  # Whether to enable Markdown rendering in the Nix binary.
+  enableMarkdown ? !stdenv.hostPlatform.isWindows,
 
-# Which interactive line editor library to use for Nix's repl.
-#
-# Currently supported choices are:
-#
-# - editline (default)
-# - readline
-, readlineFlavor ? if stdenv.hostPlatform.isWindows then "readline" else "editline"
+  # Which interactive line editor library to use for Nix's repl.
+  #
+  # Currently supported choices are:
+  #
+  # - editline (default)
+  # - readline
+  readlineFlavor ? if stdenv.hostPlatform.isWindows then "readline" else "editline",
 }:
 
 let