Add a comments to rollback from .po about empty events that break files

README.md

@@ -44,4 +44,12 @@ To convert back from po:
 
 ```bash
 echo "start at $(date)"; time for i in Translation/fr/po/Modules/*; do echo "rollback ${i}..."; time ./rollback_module.sh "${i}" fr; echo "done"; done; echo "end at $(date)";
-```
+```
+
+**Warning** : Empty events are not recreated (as they disappear on .pot), so be careful:
+ - search for this in the Modules/game_files/*.txt
+ ```bash
+-- \[EVENT\].*$
+\[/EVENT\]
+```
+ - Report all empty events in the corresponding txt in Translation/modules