pgsql: Modify the built-in text search parser to handle URLs more nearly

Log Message:
-----------
Modify the built-in text search parser to handle URLs more nearly according
to RFC 3986.  In particular, these characters now terminate the path part
of a URL: '"', '<', '>', '\', '^', '`', '{', '|', '}'.  The previous behavior
was inconsistent and depended on whether a "?" was present in the path.
Per gripe from Donald Fraser and spec research by Kevin Grittner.

This is a pre-existing bug, but not back-patching since the risks of
breaking existing applications seem to outweigh the benefits.

Modified Files:
--------------
    pgsql/src/backend/tsearch:
        wparser_def.c (r1.29 -> r1.30)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/tsearch/wparser_def.c?r1=1.29&r2=1.30)
    pgsql/src/test/regress/expected:
        tsearch.out (r1.17 -> r1.18)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/tsearch.out?r1=1.17&r2=1.18)
    pgsql/src/test/regress/sql:
        tsearch.sql (r1.11 -> r1.12)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/tsearch.sql?r1=1.11&r2=1.12)