home: jujutsu: set 'ui.diff-formatter'

I *still* don't really like the built-in formatting, but it's more about
its highlighting than its syntax.

Given that I default to using `delta` anyways, it doesn't _really_
matter as I don't see the default output.

modules/home/jujutsu/default.nix

@@ -40,6 +40,11 @@ in
           lola = [ "lol" "-r" "all()" ];
         };
 
+        ui = {
+          # I don't like word-diff
+          diff-formatter = ":git";
+        };
+
         "--scope" = [
           # Multiple identities
           {