BUG #9038: trgm must have operand in index creation

The following bug has been logged on the website:

Bug reference:      9038
Logged by:          Craig Macdonald
Email address:      craig.macdonald@glasgow.ac.uk
PostgreSQL version: 9.2.0
Operating system:   Documentation
Description:

The documentation at
http://www.postgresql.org/docs/9.2/static/textsearch-indexes.html
is incorrect in the syntax of CREATE INDEX for GIN and GIST. According to
http://www.postgresql.org/docs/9.2/static/pgtrgm.html the keyword
gist_trgm_ops is also necessary:

test=> CREATE INDEX trgm_idx ON test_trgm USING gist (t);
ERROR:  data type text has no default operator class for access method
"gist"
test=> CREATE INDEX trgm_idx ON test_trgm USING gist (t gist_trgm_ops);
CREATE INDEX