$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/libxklavier/default.nix

@@ -12,7 +12,7 @@ stdenv.mkDerivation rec {
     sha256 = "016lpdv35z0qsw1cprdc2k5qzkdi5waj6qmr0a2q6ljn9g2kpv7b";
   };
 
-  outputs = [ "dev" "out" "doc" ]; # dev-doc only
+  outputs = [ "dev" "out" "docdev" ];
 
   # TODO: enable xmodmap support, needs xmodmap DB
   propagatedBuildInputs = with xorg; [ libX11 libXi xkeyboard_config libxml2 libICE glib libxkbfile isocodes ];