Multiline string using $REDSHIFT$ token is not supported

Example query:

```sql
select *
from dblink('hosting_insights',$REDSHIFT$
SELECT distinct hm_user.company
FROM metabase_database
LEFT JOIN hm_hosted_instance
ON metabase_database.etl_source_instance_id = hm_hosted_instance.id
LEFT JOIN hm_user
ON hm_hosted_instance.owner_id = hm_user.id
WHERE metabase_database.is_sample = FALSE
$REDSHIFT$) as t1(customer text)
```

Interestingly enough, this is a `:postgres` query on Stats...

**Queries affected on Stas:** 93

Start with the reported SQL example and the repository’s JSqlParser integration, then reproduce parsing of the $REDSHIFT$-delimited multiline string. Done means the query parses successfully and a regression test covers this token format.

Written by the indexing model from the issue text.