$docdev fixups: mostly to avoid empty output

... after auto-removing some kinds of files by default.
In some cases I let them be removed and in others I let them be put into
$docdev. That was more due to general indecisiveness on this question
than any reasons in the particular cases.

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

@@ -8,7 +8,7 @@ stdenv.mkDerivation rec {
     sha256 = "1f5dfxjnil2glfwxnqr14d2cjfbkghsbsn8n04js2c2icr7iv2pv";
   };
 
-  outputs = [ "out" "doc" ];
+  outputs = [ "out" "docdev" ];
 
   configureFlags = "--disable-introspection";