source-han-{sans,serif,mono}: {update,refactor,init}

* source-han-sans: 1.004R -> 2.001
* source-han-serif: switch to Super OTC
* source-han-mono: init at 1.002

The Source Han fonts now use shared package infrastructure, and the
Super OTC distributions, which unify the various scripts into a single
bundle file, improving automatic font selection and reducing overall
disk space usage. This also means that the Traditional
Chinese—Hong Kong language variant is now included.

The old package names including language are aliased to the Super OTC
bundle packages.

pkgs/data/fonts/source-han/default.nix

@@ -0,0 +1,54 @@
+{ stdenvNoCC
+, lib
+, fetchzip
+, fetchurl
+}:
+
+let
+  makePackage = { family, description, rev, sha256 }: let
+    Family =
+      lib.toUpper (lib.substring 0 1 family) +
+      lib.substring 1 (lib.stringLength family) family;
+
+    ttc = fetchurl {
+      url = "https://github.com/adobe-fonts/source-han-${family}/releases/download/${rev}/SourceHan${Family}.ttc";
+      inherit sha256;
+    };
+  in stdenvNoCC.mkDerivation {
+    pname = "source-han-${family}";
+    version = lib.removeSuffix "R" rev;
+
+    buildCommand = ''
+      install -m444 -Dt $out/share/fonts/opentype/source-han-${family} ${ttc}
+    '';
+
+    meta = {
+      description = "An open source Pan-CJK ${description} typeface";
+      homepage = "https://github.com/adobe-fonts/source-han-${family}";
+      license = lib.licenses.ofl;
+      maintainers = with lib.maintainers; [ taku0 emily ];
+    };
+  };
+in
+{
+  sans = makePackage {
+    family = "sans";
+    description = "sans-serif";
+    rev = "2.001R";
+    sha256 = "101p8q0sagf1sd1yzwdrmmxvkqq7j0b8hi0ywsfck9w56r4zx54y";
+  };
+
+  serif = makePackage {
+    family = "serif";
+    description = "serif";
+    rev = "1.001R";
+    sha256 = "1d968h30qvvwy3s77m9y3f1glq8zlr6bnfw00yinqa18l97n7k45";
+  };
+
+  mono = makePackage {
+    family = "mono";
+    description = "monospaced";
+    rev = "1.002";
+    sha256 = "1haqffkcgz0cc24y8rc9bg36v8x9hdl8fdl3xc8qz14hvr42868c";
+  };
+}