There is missing documentation for custom query for PostgreSQL plugin for Zabbix agent 2

• https://www.zabbix.com/documentation/5.0/en/manual/config/items/plugins
• https://www.zabbix.com/documentation/5.0/en/manual/config/items/itemtypes/zabbix_agent/zabbix_agent2
• https://www.zabbix.com/documentation/5.0/en/manual/appendix/config/zabbix_agent2

The needed information can be found in the plugin readme:

• https://git.zabbix.com/projects/ZBX/repos/zabbix/browse/src/go/plugins/postgres/README.md?at=release/5.0