git-cliff: add module

modules/programs/git-cliff.nix

@@ -0,0 +1,45 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.programs.git-cliff;
+  tomlFormat = pkgs.formats.toml { };
+
+in {
+  meta.maintainers = [ hm.maintainers.NateCox ];
+
+  options.programs.git-cliff = {
+    enable = mkEnableOption "git-cliff changelog generator";
+
+    package = mkPackageOption pkgs "git-cliff" { };
+
+    settings = mkOption {
+      type = tomlFormat.type;
+      default = { };
+      example = literalExpression ''
+        {
+          header = "Changelog";
+          trim = true;
+        }
+      '';
+      description = ''
+        Configuration written to
+        <filename>$XDG_CONFIG_HOME/git-cliff/cliff.toml</filename>. See
+        <link xlink:href="https://git-cliff.org/docs/configuration" />
+        for the documentation.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    home.packages = [ cfg.package ];
+
+    xdg.configFile = {
+      "git-cliff/cliff.toml" = mkIf (cfg.settings != { }) {
+        source = tomlFormat.generate "git-cliff-config" cfg.settings;
+      };
+    };
+  };
+}