Thread: pgsql: Improve psql's \dC command to take a pattern parameter.

Log Message:
-----------
Improve psql's \dC command to take a pattern parameter.  Casts are shown
if their source or target types match the pattern (using the same definition
of "match" as \dT does).  Per recent discussion.

Modified Files:
--------------
    pgsql/doc/src/sgml/ref:
        psql-ref.sgml (r1.211 -> r1.212)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/psql-ref.sgml?r1=1.211&r2=1.212)
    pgsql/src/bin/psql:
        describe.c (r1.186 -> r1.187)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/describe.c?r1=1.186&r2=1.187)
        help.c (r1.130 -> r1.131)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/help.c?r1=1.130&r2=1.131)