mkSymlinkActivationScript: remove unnecessary isDir arg

flake.nix

@@ -11,9 +11,9 @@
       (mkIf (!p) no)
     ];
 
-    mkSymlinkActivationScript = {target, source, isDir ? false}: ''
+    mkSymlinkActivationScript = {target, source}: ''
       if [ -e ${target} ]; then
-        rm${if isDir then " -rf" else ""} ${target}
+        rm -rf ${target}
       fi
       ln -s ${source} ${target}
     '';