Update the description of the skipped.operations property that was added in DBZ-5610 to apply consistent description list formatting as in the Oracle connector doc, and improve clarity. This change applies to Debezium connectors for Db2, MongoDB, MySQL, MariaDB, PostgreSQL, SQL Server, and Vitess.

Also update the description that 5610 added to the Truncate events section in mysql.adoc of the truncate event source field, and apply the changes to the equivalent section in oracle.adoc and postgresql.adoc