graphical/mpv: reduce arrowkey seek to 2 seconds

graphical/mpv.nix

@@ -29,6 +29,14 @@ in
         screenshot-webp-lossless=yes
       '';
     };
+
+    extraInputConf = lib.mkOption {
+      type = lib.types.lines;
+      default = ''
+        RIGHT seek 2
+        LEFT seek -2
+      '';
+    };
   };
 
   config = lib.mkIf cfg.enable {
@@ -36,7 +44,15 @@ in
       (cfg.package.override {
         extraMakeWrapperArgs = [
           "--add-flags"
-          "--config-dir=${pkgs.writeTextDir "${name}.conf" cfg.extraConfig}"
+          "--config-dir=${
+            pkgs.symlinkJoin {
+              inherit name;
+              paths = [
+                (pkgs.writeTextDir "${name}.conf" cfg.extraConfig)
+                (pkgs.writeTextDir "input.conf" cfg.extraInputConf)
+              ];
+            }
+          }"
         ];
       })
     ];