* Remove one unnecessary pg_class join in SQL command.  Not needed,
  because we use a regclass cast instead.

* Doc: refer to "partitioned relations" rather than specifically tables,
  since indexes are also displayed.

* Rename "On table" column to "Table", for consistency with \di.

Author: Justin Pryzby
Discussion: https://postgr.es/m/20190407212525.GB10080@telsasoft.com