$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/libraries/gmime/default.nix

@@ -8,7 +8,7 @@ stdenv.mkDerivation rec {
     sha256 = "0rfzbgsh8ira5p76kdghygl5i3fvmmx4wbw5rp7f8ajc4vxp18g0";
   };
 
-  outputs = [ "dev" "out" "doc" ];
+  outputs = [ "dev" "out" ];
 
   nativeBuildInputs = [ pkgconfig ];
   propagatedBuildInputs = [ glib zlib libgpgerror ];