pgsql: Improve unique-constraint-violation error messages to include the

Log Message:
-----------
Improve unique-constraint-violation error messages to include the exact
values being complained of.

In passing, also remove the arbitrary length limitation in the similar
error detail message for foreign key violations.

Itagaki Takahiro

Modified Files:
--------------
    pgsql/contrib/citext/expected:
        citext.out (r1.7 -> r1.8)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/citext/expected/citext.out?r1=1.7&r2=1.8)
        citext_1.out (r1.5 -> r1.6)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/citext/expected/citext_1.out?r1=1.5&r2=1.6)
    pgsql/src/backend/access/common:
        indextuple.c (r1.88 -> r1.89)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/common/indextuple.c?r1=1.88&r2=1.89)
    pgsql/src/backend/access/index:
        genam.c (r1.74 -> r1.75)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/index/genam.c?r1=1.74&r2=1.75)
    pgsql/src/backend/access/nbtree:
        nbtinsert.c (r1.171 -> r1.172)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/nbtree/nbtinsert.c?r1=1.171&r2=1.172)
    pgsql/src/backend/utils/adt:
        ri_triggers.c (r1.113 -> r1.114)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/ri_triggers.c?r1=1.113&r2=1.114)
        ruleutils.c (r1.305 -> r1.306)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/ruleutils.c?r1=1.305&r2=1.306)
    pgsql/src/include/access:
        genam.h (r1.79 -> r1.80)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/access/genam.h?r1=1.79&r2=1.80)
        itup.h (r1.51 -> r1.52)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/access/itup.h?r1=1.51&r2=1.52)
    pgsql/src/include/utils:
        builtins.h (r1.335 -> r1.336)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/builtins.h?r1=1.335&r2=1.336)
    pgsql/src/interfaces/ecpg/test/expected:
        compat_informix-test_informix.stderr (r1.12 -> r1.13)

(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/test/expected/compat_informix-test_informix.stderr?r1=1.12&r2=1.13)
    pgsql/src/test/regress/expected:
        alter_table.out (r1.116 -> r1.117)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/alter_table.out?r1=1.116&r2=1.117)
        arrays.out (r1.48 -> r1.49)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/arrays.out?r1=1.48&r2=1.49)
        create_index.out (r1.31 -> r1.32)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/create_index.out?r1=1.31&r2=1.32)
        inherit.out (r1.26 -> r1.27)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/inherit.out?r1=1.26&r2=1.27)
        plpgsql.out (r1.71 -> r1.72)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/plpgsql.out?r1=1.71&r2=1.72)
        transactions.out (r1.18 -> r1.19)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/transactions.out?r1=1.18&r2=1.19)
        uuid.out (r1.4 -> r1.5)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/uuid.out?r1=1.4&r2=1.5)
    pgsql/src/test/regress/output:
        constraints.source (r1.44 -> r1.45)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/output/constraints.source?r1=1.44&r2=1.45)
        tablespace.source (r1.7 -> r1.8)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/output/tablespace.source?r1=1.7&r2=1.8)