cleanup whitespace and commas

* [] is now [ ]
* {} is now { }
* commas in arglists go at end of line not beginning

In short, I ran the whole thing through nixfmt-rfc-style but only
accepted about 30% of its changes. I might grow accustomed to more
of it over time

pkgs/pseudofile/default.nix

@@ -1,7 +1,4 @@
-{
-  writeText
-, lib
-}:
+{ writeText, lib }:
 let
   inherit (lib.attrsets) mapAttrsToList;
   visit = prefix: attrset: