Update troubleshooting.mdx (#11239)

Add `DAY` in the `INTERVAL` keyword used to manually purge the nodestore_node table to prevent accidentally purging (almost) the entire table.

develop-docs/self-hosted/troubleshooting.mdx

@@ -163,7 +163,7 @@ docker compose run --rm -T postgres bash -c "apt update && apt install -y --no-i
 
 If the script above still does not clear up enough disk space, you can try the following in Postgres. This will lead to data loss in event details. _SENTRY_RETENTION_DAYS_ will need to be filled in manually.
 ```sql
-DELETE FROM public.nodestore_node WHERE "timestamp" < NOW() - INTERVAL '[SENTRY_RETENTION_DAYS]';
+DELETE FROM public.nodestore_node WHERE "timestamp" < NOW() - INTERVAL '[SENTRY_RETENTION_DAYS] DAY';
 VACUUM FULL public.nodestore_node;
 ```