pkgs/data/fonts: merge back the split otb output

Since the Pango issue 457[1] has been fixed and Nixpkgs patched, it's no
longer necessary to keep X11 and .otb fonts in separate outputs (previously
they would cause application to display broken fonts).

[1]: https://gitlab.gnome.org/GNOME/pango/-/issues/457

pkgs/data/fonts/unifont/default.nix

@@ -30,8 +30,8 @@ stdenv.mkDerivation rec {
   installPhase =
     ''
       # install otb fonts
-      install -m 644 -D unifont.otb "$otb/share/fonts/unifont.otb"
-      mkfontdir "$otb/share/fonts"
+      install -m 644 -D unifont.otb "$out/share/fonts/unifont.otb"
+      mkfontdir "$out/share/fonts"
 
       # install pcf and ttf fonts
       install -m 644 -D ${pcf} $out/share/fonts/unifont.pcf.gz
@@ -41,8 +41,6 @@ stdenv.mkDerivation rec {
       mkfontscale
     '';
 
-  outputs = [ "out" "otb" ];
-
   meta = with stdenv.lib; {
     description = "Unicode font for Base Multilingual Plane";
     homepage = "http://unifoundry.com/unifont.html";