treewide: with stdenv.lib; in meta -> with lib;

Part of: https://github.com/NixOS/nixpkgs/issues/108938

meta = with stdenv.lib;

is a widely used pattern. We want to slowly remove
the `stdenv.lib` indirection and encourage people
to use `lib` directly. Thus let’s start with the meta
field.

This used a rewriting script to mostly automatically
replace all occurances of this pattern, and add the
`lib` argument to the package header if it doesn’t
exist yet.

The script in its current form is available at
https://cs.tvl.fyi/depot@2f807d7f141068d2d60676a89213eaa5353ca6e0/-/blob/users/Profpatsch/nixpkgs-rewriter/default.nix

pkgs/development/python-modules/gast/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchPypi, buildPythonPackage, astunparse }:
+{ lib, stdenv, fetchPypi, buildPythonPackage, astunparse }:
 
 buildPythonPackage rec {
   pname = "gast";
@@ -8,7 +8,7 @@ buildPythonPackage rec {
     sha256 = "40feb7b8b8434785585ab224d1568b857edb18297e5a3047f1ba012bc83b42c1";
   };
   checkInputs = [ astunparse ] ;
-  meta = with stdenv.lib; {
+  meta = with lib; {
     description = "GAST provides a compatibility layer between the AST of various Python versions, as produced by ast.parse from the standard ast module.";
     license = licenses.bsd3;
     maintainers = with maintainers; [ jyp ];