zsh: Make cp use reflinks if possible

users/simon/modules/zsh.nix

@@ -49,6 +49,7 @@ in
         }
       ];
       shellAliases = {
+        cp = "cp --reflink=auto"; # TODO: remove with coreutils > 8.32
         exa = "exa --git --binary";
         ipy = "ipython3";
         l = "exa -l";