Revise command completion tags as per hackers message on 20 March.

doc/src/sgml/ref/alter_table.sgml

doc/src/sgml/ref/alter_trigger.sgml

doc/src/sgml/ref/close.sgml

doc/src/sgml/ref/create_aggregate.sgml

doc/src/sgml/ref/create_constraint.sgml

doc/src/sgml/ref/create_index.sgml

doc/src/sgml/ref/create_language.sgml

doc/src/sgml/ref/create_operator.sgml

doc/src/sgml/ref/create_rule.sgml

doc/src/sgml/ref/create_schema.sgml

doc/src/sgml/ref/create_sequence.sgml

doc/src/sgml/ref/create_table.sgml

doc/src/sgml/ref/create_trigger.sgml

doc/src/sgml/ref/create_type.sgml

doc/src/sgml/ref/create_view.sgml

doc/src/sgml/ref/declare.sgml

doc/src/sgml/ref/drop_aggregate.sgml

doc/src/sgml/ref/drop_domain.sgml

doc/src/sgml/ref/drop_function.sgml

doc/src/sgml/ref/drop_index.sgml