Thread: pgsql: Add some knowledge about prefix matches to tsmatchsel().

Log Message:
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Add some knowledge about prefix matches to tsmatchsel().  It's not terribly
bright, but it beats assuming that a prefix match behaves identically to an
exact match, which is what the code was doing before :-(.  Noted while
experimenting with Artur Dobrowski's example.

Modified Files:
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    pgsql/src/backend/tsearch:
        ts_selfuncs.c (r1.8 -> r1.9)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/tsearch/ts_selfuncs.c?r1=1.8&r2=1.9)