theme-obsidian2: reformat nix expression

pkgs/data/themes/obsidian2/default.nix

@@ -1,4 +1,8 @@
-{ lib, stdenv, fetchurl, gtk-engine-murrine }:
+{ lib
+, stdenv
+, fetchurl
+, gtk-engine-murrine
+}:
 
 stdenv.mkDerivation rec {
   pname = "theme-obsidian2";
@@ -11,7 +15,9 @@ stdenv.mkDerivation rec {
 
   sourceRoot = ".";
 
-  propagatedUserEnvPkgs = [ gtk-engine-murrine ];
+  propagatedUserEnvPkgs = [
+    gtk-engine-murrine
+  ];
 
   installPhase = ''
     runHook preInstall
@@ -21,7 +27,7 @@ stdenv.mkDerivation rec {
   '';
 
   meta = with lib; {
-    description = "Gnome theme, based upon Adwaita-Maia dark skin";
+    description = "Gnome theme based upon Adwaita-Maia dark skin";
     homepage = "https://github.com/madmaxms/theme-obsidian-2";
     license = with licenses; [ gpl3Only ];
     platforms = platforms.linux;