Alter trigger definition results in no diff

In case a Trigger definition gets altered no diff is generated.

DB Dumps:

old dump:

```sql
CREATE TRIGGER _tg_my_sync_trigger AFTER INSERT ON my_table FOR EACH ROW WHEN ((new.ts IS NOT NULL)) EXECUTE FUNCTION tg_add_sync();
```

vanilla dump:

```sql
CREATE TRIGGER _tg_my_sync_trigger AFTER INSERT ON my_table FOR EACH ROW EXECUTE FUNCTION tg_add_sync();
```