firefox: leverage Home Manager's mkFirefoxModule pattern (#695)

Leverage Home Manager's mkFirefoxModule pattern introduced in commit
792757f643ce [1] ("firefox: support firefox derivatives").

[1]: nix-community/home-manager@792757f

Reviewed-by: NAHO <[email protected]>
Tested-by: NAHO <[email protected]>
(cherry picked from commit 079fece)

modules/firefox/hm.nix

@@ -13,20 +13,24 @@ let
   };
   makeProfileSettingsPair = profileName:
     lib.nameValuePair profileName profileSettings;
+  derivatives = [
+    {path = "firefox"; name = "Firefox";}
+    {path = "librewolf"; name = "LibreWolf";}
+  ];
 in {
-  options.stylix.targets.firefox = {
+  options.stylix.targets = lib.listToAttrs (map (drv: lib.nameValuePair drv.path {
     enable =
-      config.lib.stylix.mkEnableTarget "Firefox" true;
+      config.lib.stylix.mkEnableTarget drv.name true;
 
     profileNames = lib.mkOption {
-      description = "The Firefox profile names to apply styling on.";
+      description = "The ${drv.name} profile names to apply styling on.";
       type = lib.types.listOf lib.types.str;
       default = [ ];
     };
-  };
+  }) derivatives);
 
-  config = lib.mkIf (config.stylix.enable && config.stylix.targets.firefox.enable) {
-    programs.firefox.profiles = lib.listToAttrs
-      (map makeProfileSettingsPair config.stylix.targets.firefox.profileNames);
-  };
+  config = lib.mkMerge (map (drv: lib.mkIf (config.stylix.enable && config.stylix.targets.${drv.path}.enable) {
+    programs.${drv.path}.profiles = lib.listToAttrs
+      (map makeProfileSettingsPair config.stylix.targets.${drv.path}.profileNames);
+  }) derivatives);
 }