Improvement to pg_trgm readme

This adds mention of my latest tweak to the tsearch2/pg_trgm 
integration.  It is much better to create a word list of unstemmed words 
than stemmed ones.

Chris
Index: contrib/pg_trgm/README.pg_trgm
===================================================================
RCS file: /projects/cvsroot/pgsql/contrib/pg_trgm/README.pg_trgm,v
retrieving revision 1.1
diff -c -r1.1 README.pg_trgm
*** contrib/pg_trgm/README.pg_trgm	31 May 2004 17:18:11 -0000	1.1
--- contrib/pg_trgm/README.pg_trgm	26 Nov 2004 01:31:39 -0000
***************
*** 100,110 ****
  	The first step is to generate an auxiliary table containing all
  	the unique words in the Tsearch2 index:
  
! 	CREATE TABLE words AS 
! 		SELECT word FROM stat('SELECT vector FROM documents');
  
! 	Where 'documents' is the table that contains the Tsearch2 index
! 	column 'vector', of type 'tsvector'.
  
  	Next, create a trigram index on the word column:
  
--- 100,114 ----
  	The first step is to generate an auxiliary table containing all
  	the unique words in the Tsearch2 index:
  
! 	CREATE TABLE words AS SELECT word FROM
! 		stat('SELECT to_tsvector(''simple'', bodytext) FROM documents');
  
! 	Where 'documents' is a table that has a text field 'bodytext'
! 	that TSearch2 is used to search.  The use of the 'simple' dictionary
! 	with the to_tsvector function, instead of just using the already
! 	existing vector is to avoid creating a list of already stemmed
! 	words.  This way, only the original, unstemmed words are added
! 	to the word list.
  
  	Next, create a trigram index on the word column: