pgsql: Update reference documentation on may/can/might: Standard

Log Message:
-----------
Update reference documentation on may/can/might:

Standard English uses "may", "can", and "might" in different ways:

        may - permission, "You may borrow my rake."

        can - ability, "I can lift that log."

        might - possibility, "It might rain today."

Unfortunately, in conversational English, their use is often mixed, as
in, "You may use this variable to do X", when in fact, "can" is a better
choice.  Similarly, "It may crash" is better stated, "It might crash".

Modified Files:
--------------
    pgsql/doc/src/sgml/ref:
        alter_domain.sgml (r1.20 -> r1.21)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/alter_domain.sgml.diff?r1=1.20&r2=1.21)
        alter_index.sgml (r1.11 -> r1.12)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/alter_index.sgml.diff?r1=1.11&r2=1.12)
        alter_opfamily.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/alter_opfamily.sgml.diff?r1=1.1&r2=1.2)
        alter_sequence.sgml (r1.15 -> r1.16)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/alter_sequence.sgml.diff?r1=1.15&r2=1.16)
        alter_table.sgml (r1.92 -> r1.93)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/alter_table.sgml.diff?r1=1.92&r2=1.93)
        analyze.sgml (r1.20 -> r1.21)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/analyze.sgml.diff?r1=1.20&r2=1.21)
        begin.sgml (r1.34 -> r1.35)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/begin.sgml.diff?r1=1.34&r2=1.35)
        checkpoint.sgml (r1.14 -> r1.15)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/checkpoint.sgml.diff?r1=1.14&r2=1.15)
        cluster.sgml (r1.38 -> r1.39)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/cluster.sgml.diff?r1=1.38&r2=1.39)
        comment.sgml (r1.34 -> r1.35)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/comment.sgml.diff?r1=1.34&r2=1.35)
        copy.sgml (r1.77 -> r1.78)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/copy.sgml.diff?r1=1.77&r2=1.78)
        create_aggregate.sgml (r1.36 -> r1.37)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_aggregate.sgml.diff?r1=1.36&r2=1.37)
        create_cast.sgml (r1.23 -> r1.24)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_cast.sgml.diff?r1=1.23&r2=1.24)
        create_conversion.sgml (r1.18 -> r1.19)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_conversion.sgml.diff?r1=1.18&r2=1.19)
        create_database.sgml (r1.46 -> r1.47)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_database.sgml.diff?r1=1.46&r2=1.47)
        create_domain.sgml (r1.29 -> r1.30)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_domain.sgml.diff?r1=1.29&r2=1.30)
        create_function.sgml (r1.71 -> r1.72)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_function.sgml.diff?r1=1.71&r2=1.72)
        create_index.sgml (r1.59 -> r1.60)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_index.sgml.diff?r1=1.59&r2=1.60)
        create_language.sgml (r1.42 -> r1.43)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_language.sgml.diff?r1=1.42&r2=1.43)
        create_opclass.sgml (r1.19 -> r1.20)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_opclass.sgml.diff?r1=1.19&r2=1.20)
        create_operator.sgml (r1.46 -> r1.47)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_operator.sgml.diff?r1=1.46&r2=1.47)
        create_opfamily.sgml (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_opfamily.sgml.diff?r1=1.1&r2=1.2)
        create_role.sgml (r1.8 -> r1.9)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_role.sgml.diff?r1=1.8&r2=1.9)
        create_rule.sgml (r1.48 -> r1.49)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_rule.sgml.diff?r1=1.48&r2=1.49)
        create_schema.sgml (r1.18 -> r1.19)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_schema.sgml.diff?r1=1.18&r2=1.19)
        create_sequence.sgml (r1.45 -> r1.46)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_sequence.sgml.diff?r1=1.45&r2=1.46)
        create_table.sgml (r1.105 -> r1.106)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_table.sgml.diff?r1=1.105&r2=1.106)
        create_tablespace.sgml (r1.7 -> r1.8)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_tablespace.sgml.diff?r1=1.7&r2=1.8)
        create_trigger.sgml (r1.45 -> r1.46)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_trigger.sgml.diff?r1=1.45&r2=1.46)
        create_type.sgml (r1.66 -> r1.67)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_type.sgml.diff?r1=1.66&r2=1.67)
        create_view.sgml (r1.33 -> r1.34)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_view.sgml.diff?r1=1.33&r2=1.34)
        declare.sgml (r1.39 -> r1.40)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/declare.sgml.diff?r1=1.39&r2=1.40)
        delete.sgml (r1.28 -> r1.29)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/delete.sgml.diff?r1=1.28&r2=1.29)
        drop_conversion.sgml (r1.10 -> r1.11)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/drop_conversion.sgml.diff?r1=1.10&r2=1.11)
        drop_function.sgml (r1.32 -> r1.33)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/drop_function.sgml.diff?r1=1.32&r2=1.33)
        drop_language.sgml (r1.23 -> r1.24)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/drop_language.sgml.diff?r1=1.23&r2=1.24)
        drop_opclass.sgml (r1.11 -> r1.12)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/drop_opclass.sgml.diff?r1=1.11&r2=1.12)
        drop_owned.sgml (r1.4 -> r1.5)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/drop_owned.sgml.diff?r1=1.4&r2=1.5)
        drop_table.sgml (r1.25 -> r1.26)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/drop_table.sgml.diff?r1=1.25&r2=1.26)
        drop_tablespace.sgml (r1.5 -> r1.6)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/drop_tablespace.sgml.diff?r1=1.5&r2=1.6)
        ecpg-ref.sgml (r1.31 -> r1.32)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/ecpg-ref.sgml.diff?r1=1.31&r2=1.32)
        explain.sgml (r1.38 -> r1.39)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/explain.sgml.diff?r1=1.38&r2=1.39)
        grant.sgml (r1.62 -> r1.63)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/grant.sgml.diff?r1=1.62&r2=1.63)
        initdb.sgml (r1.38 -> r1.39)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/initdb.sgml.diff?r1=1.38&r2=1.39)
        insert.sgml (r1.34 -> r1.35)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/insert.sgml.diff?r1=1.34&r2=1.35)
        ipcclean.sgml (r1.13 -> r1.14)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/ipcclean.sgml.diff?r1=1.13&r2=1.14)
        load.sgml (r1.23 -> r1.24)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/load.sgml.diff?r1=1.23&r2=1.24)
        notify.sgml (r1.28 -> r1.29)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/notify.sgml.diff?r1=1.28&r2=1.29)
        pg_config-ref.sgml (r1.25 -> r1.26)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/pg_config-ref.sgml.diff?r1=1.25&r2=1.26)
        pg_controldata.sgml (r1.8 -> r1.9)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/pg_controldata.sgml.diff?r1=1.8&r2=1.9)
        pg_ctl-ref.sgml (r1.37 -> r1.38)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/pg_ctl-ref.sgml.diff?r1=1.37&r2=1.38)
        pg_dump.sgml (r1.92 -> r1.93)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/pg_dump.sgml.diff?r1=1.92&r2=1.93)
        pg_dumpall.sgml (r1.63 -> r1.64)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/pg_dumpall.sgml.diff?r1=1.63&r2=1.64)
        pg_resetxlog.sgml (r1.19 -> r1.20)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/pg_resetxlog.sgml.diff?r1=1.19&r2=1.20)
        pg_restore.sgml (r1.64 -> r1.65)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/pg_restore.sgml.diff?r1=1.64&r2=1.65)
        postgres-ref.sgml (r1.48 -> r1.49)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/postgres-ref.sgml.diff?r1=1.48&r2=1.49)
        prepare.sgml (r1.21 -> r1.22)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/prepare.sgml.diff?r1=1.21&r2=1.22)
        psql-ref.sgml (r1.180 -> r1.181)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/psql-ref.sgml.diff?r1=1.180&r2=1.181)
        reindex.sgml (r1.35 -> r1.36)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/reindex.sgml.diff?r1=1.35&r2=1.36)
        release_savepoint.sgml (r1.6 -> r1.7)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/release_savepoint.sgml.diff?r1=1.6&r2=1.7)
        revoke.sgml (r1.41 -> r1.42)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/revoke.sgml.diff?r1=1.41&r2=1.42)
        select.sgml (r1.96 -> r1.97)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/select.sgml.diff?r1=1.96&r2=1.97)
        set_role.sgml (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/set_role.sgml.diff?r1=1.3&r2=1.4)
        set_session_auth.sgml (r1.15 -> r1.16)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/set_session_auth.sgml.diff?r1=1.15&r2=1.16)
        start_transaction.sgml (r1.15 -> r1.16)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/start_transaction.sgml.diff?r1=1.15&r2=1.16)
        truncate.sgml (r1.21 -> r1.22)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/truncate.sgml.diff?r1=1.21&r2=1.22)
        unlisten.sgml (r1.28 -> r1.29)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/unlisten.sgml.diff?r1=1.28&r2=1.29)
        update.sgml (r1.41 -> r1.42)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/update.sgml.diff?r1=1.41&r2=1.42)
        vacuum.sgml (r1.46 -> r1.47)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/vacuum.sgml.diff?r1=1.46&r2=1.47)
        vacuumdb.sgml (r1.37 -> r1.38)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/vacuumdb.sgml.diff?r1=1.37&r2=1.38)
        values.sgml (r1.2 -> r1.3)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/values.sgml.diff?r1=1.2&r2=1.3)