python3Packages.docutils: Fix upstream URL (repo.or.cz -> sourceforge)

I am seeing frequent HTTP 503 Service Unavailable responses from
repo.or.cz, and I'm looking for an alternative upstream.

The project's ultimate upstream appears to be SourceForge: the project
homepage is hosted by SourceForge and the README references SourceForge
as the ultimate source of releases.

https://docutils.sourceforge.io/docs/dev/repository.html mentions the
Git mirror at repo.or.cz, but this appears to be more of a (read-only?)
convenience for project developers that prefer Git. There is also this
footnote:

  There are also 3rd-party mirrors and forks at GitHub, some of them
  orphaned. At the time of this writing (2021-11-03),
  https://github.com/live-clones/docutils/tree/master/docutils provides
  an hourly updated clone.

but this clone does not contain release tags.

Due to how this project is organized and the connectivity problems to
repo.or.cz, I suspect that the releases hosted on SourceForge are a
better upstream for nixpkgs, than to download corresponding releases
from the Git mirror at repo.or.cz.

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

@@ -1,6 +1,6 @@
 {
   lib,
-  fetchFromRepoOrCz,
+  fetchurl,
   buildPythonPackage,
   flit-core,
   pillow,
@@ -19,10 +19,9 @@ let
 
     disabled = pythonOlder "3.7";
 
-    src = fetchFromRepoOrCz {
-      repo = "docutils";
-      rev = "docutils-${version}";
-      hash = "sha256-Q+9yW+BYUEvPYV504368JsAoKKoaTZTeKh4tVeiNv5Y=";
+    src = fetchurl {
+      url = "mirror://sourceforge/docutils/docutils-${version}.tar.gz";
+      hash = "sha256-OmsYcy7fGC2qPNEndbuzOM9WkUaPke7rEJ3v9uv6mG8=";
     };
 
     build-system = [ flit-core ];
@@ -53,7 +52,7 @@ let
         psfl
         gpl3Plus
       ];
-      maintainers = with maintainers; [ ];
+      maintainers = with maintainers; [ jherland ];
     };
   };
 in