docutils: Install compat symlinks

E.g. latest upstream version of diffoscope depends on a command named
rst2man.

pkgs/top-level/python-packages.nix

@@ -7915,6 +7915,13 @@ in {
     # error: invalid command 'test'
     doCheck = false;
 
+    # Create symlinks lacking a ".py" suffix, many programs depend on these names
+    postFixup = ''
+      (cd $out/bin && for f in *.py; do
+        ln -s $f $(echo $f | sed -e 's/\.py$//')
+      done)
+    '';
+
     meta = {
       description = "An open-source text processing system for processing plaintext documentation into useful formats, such as HTML or LaTeX";
       homepage = http://docutils.sourceforge.net/;