xmobar: document how to visualize modified configuration

nix/configurations/vanadium/home/xmobar.nix

@@ -24,7 +24,8 @@
       # Xmobar uses the directory to compile too,
       # Linking the entire folder directly would make the directory not writable
       #
-      # We need to clean up the xmobar executable so it recompiles
+      # Just relink the file if you want to debug it quickly
+      # We need to clean up the xmobar executable so it recompiles (it's copied to store)
       recursive = true;
       source = "${./xmobar}";
     };