Add explicit TODO comment in preinstall script for macOS

dist-assets/pkg-scripts/preinstall

@@ -6,7 +6,9 @@ INSTALL_DIR=$2
 
 # Workaround for issue in electron-builder where the pkg-scripts are run twice, once with the
 # correct install dir and once with an incorrect one. This guard prevents running the script when
-# called the second time. This can be reverted when the following issue has been fixed:
+# called the second time.
+#
+# TODO: This can be reverted when the following issue has been fixed:
 # https://github.com/electron-userland/electron-builder/issues/8166
 if [[ $INSTALL_DIR == *"Mullvad VPN.app" ]]; then
     exit 0