another typo in parallel.sgml

I think I found a typo in parallel.sgml.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp
diff --git a/doc/src/sgml/parallel.sgml b/doc/src/sgml/parallel.sgml
index c80d42d..1e71529 100644
--- a/doc/src/sgml/parallel.sgml
+++ b/doc/src/sgml/parallel.sgml
@@ -241,7 +241,7 @@ EXPLAIN SELECT * FROM pgbench_accounts WHERE filler LIKE '%x%';    than normal but would produce
incorrectresults.  Instead, the parallel    portion of the plan must be what is known internally to the query
optimizeras a <firstterm>partial plan</>; that is, it must constructed
 
-    so that each process will which executes the plan will generate only a
+    so that each process which executes the plan will generate only a    subset of the output rows in such a way that
eachrequired output row    is guaranteed to be generated by exactly one of the cooperating processes.  </para>