Refine some things to create better looking man pages.

doc/src/sgml/ref/alter_table.sgml

doc/src/sgml/ref/begin.sgml

doc/src/sgml/ref/commit.sgml

doc/src/sgml/ref/create_function.sgml

doc/src/sgml/ref/create_index.sgml

doc/src/sgml/ref/create_table.sgml

doc/src/sgml/ref/create_table_as.sgml

doc/src/sgml/ref/createdb.sgml

doc/src/sgml/ref/createlang.sgml

doc/src/sgml/ref/createuser.sgml

doc/src/sgml/ref/declare.sgml

doc/src/sgml/ref/drop_aggregate.sgml

doc/src/sgml/ref/drop_function.sgml

doc/src/sgml/ref/drop_index.sgml

doc/src/sgml/ref/drop_language.sgml

doc/src/sgml/ref/drop_operator.sgml

doc/src/sgml/ref/dropdb.sgml

doc/src/sgml/ref/droplang.sgml

doc/src/sgml/ref/dropuser.sgml

doc/src/sgml/ref/ecpg-ref.sgml