todo: expand info a bit

TODOs.md

@@ -1,7 +1,11 @@
-# Example of automated checks from Lily Foster in the NixOS matrix room.
+- [ ] Build standalone `xin` tool for ci / deployment.
+- [ ] Add smarter checks
 
+# Example of automated checks from Lily Foster in the NixOS matrix room.
+```
    checks = with unstable.lib;
      foldl' recursiveUpdate { } (mapAttrsToList (name: system: {
        "${system.pkgs.stdenv.hostPlatform.system}"."${name}" =
          system.config.system.build.toplevel;
      }) self.nixosConfigurations);
+```