docs: Include database collation check on SQL from alter_collation.sgml

Hi,

The ALTER COLLATION documentation section include a SQL that can be used
to identity all collations in the current database that need to be
refreshed due to a collation version miss match and the objects that
depend on them. However if there is objects that use the database
collation these objects are not returned by the query.

The attached patch change the query to include the database collation
check to report collation version miss match for objects that use the
database default collation as they are not stored on pg_depend.

--
Matheus Alcantara
EDB: https://www.enterprisedb.com