Revert "gtk-doc: fix css file permissions"

This reverts commit 0e2768050a7fee157556679b31773b75a935d01d.
Let's revert the gtk-doc update for now; it causes too many problems.

pkgs/development/tools/documentation/gtk-doc/0001-highlight-fix-permission-on-file-style.patch

@@ -1,24 +0,0 @@
-From 95a75c95c5c4e641ce7cda0ded968d66f07f822a Mon Sep 17 00:00:00 2001
-From: worldofpeace <worldofpeace@protonmail.ch>
-Date: Sat, 18 May 2019 14:44:08 -0400
-Subject: [PATCH] highlight: fix permission on file style
-
----
- gtkdoc/highlight.py | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/gtkdoc/highlight.py b/gtkdoc/highlight.py
-index 8f6e470..d11c432 100644
---- a/gtkdoc/highlight.py
-+++ b/gtkdoc/highlight.py
-@@ -47,6 +47,6 @@ def highlight_code(code, lang='c'):
- 
- 
- def append_style_defs(css_file_name):
--    os.chmod(css_file_name, stat.S_IWRITE)
-+    os.chmod(css_file_name, 0o664)
-     with open(css_file_name, 'at', newline='\n', encoding='utf-8') as css:
-         css.write(HTML_FORMATTER.get_style_defs())
--- 
-2.21.0
-

pkgs/development/tools/documentation/gtk-doc/default.nix

@@ -27,8 +27,6 @@ stdenv.mkDerivation rec {
 
   patches = [
     passthru.respect_xml_catalog_files_var_patch
-    # https://gitlab.gnome.org/GNOME/gtk-doc/issues/84
-    ./0001-highlight-fix-permission-on-file-style.patch
   ];
 
   outputDevdoc = "out";