Add tag to the dollar-quoting definition of the function

This change makes the code more consistent (all the other functions also have this tag). 

And will also allow the script to be executed inside of a anonymous blocks, which are usually written as 

```sql
DO $$
   ...
$$
```

Author: paulovieira

audit.sql

@@ -232,9 +232,9 @@ $body$ LANGUAGE SQL;
 -- And provide a convenience call wrapper for the simplest case
 -- of row-level logging with no excluded cols and query logging enabled.
 --
-CREATE OR REPLACE FUNCTION audit.audit_table(target_table regclass) RETURNS void AS $$
+CREATE OR REPLACE FUNCTION audit.audit_table(target_table regclass) RETURNS void AS $body$
 SELECT audit.audit_table($1, BOOLEAN 't', BOOLEAN 't');
-$$ LANGUAGE 'sql';
+$body$ LANGUAGE 'sql';
 
 COMMENT ON FUNCTION audit.audit_table(regclass) IS $body$
 Add auditing support to the given table. Row-level changes will be logged with full client query text. No cols are ignored.