Fix doc typos and minor format glitches for downstream rendering

After fetching content from master, and building the downstream Debezium User Guide, I found that these updates are needed: 

• postgresql.adoc
  • Update the annotations for the descriptions of change events. The delete event section is missing its
    // Type: continue
    annotation. And there should no longer be separate xrefs for the specific kinds of event types. 
  • Check toplevel product-only list of xrefs - should point to new assembly anchor ID for deployment
  • In the new deployment content, there is a plus sign missing before “The command creates a Docker ….”
  • Also in the new deployment section, in the EOF step, replace << with & less than attributes and replace > with ampersand greater than attribute.
  • Also in new deployment section, add “subs-”+attributes” to the source listing that refers to the KafkaConnectorAPI version. Probably need to make sure it uses the attribute. 
  • ref-descriptions-of-debezium-postgresql-connector-configuration-properties
    The include.list property has a period where it needs a hyphen in the anchor ID. - couldn't find this, hopefully it was fixed. 

• mysql.adoc
  • ref-monitoring-debezium-mysql-connector-binlog-reading has a period where it needs a comma in the <<  >> link for NotWellFormedWhatevers
  • upstream typo, there is a space in the anchor ID for: monitoring-debezium-mysql-connector-schema history

• db2.adoc
  • Search for “<>” and insert 1. - couldn't find this. Hopefully, it was fixed already. 
  • This is causing a downstream problem so move one of them to be before the annotations and then add a blank line. 
    [[db2-example]]

                      [[db2-example-configuration]]

• event-flattening.adoc
  • The Behavior section is not getting split properly. Maybe add a source anchor ID?