docs: improve CREATE TRIGGER defer options list

Report by Jeff Davis

Author: bmomjian

doc/src/sgml/ref/create_trigger.sgml

@@ -24,7 +24,7 @@ PostgreSQL documentation
 CREATE [ CONSTRAINT ] TRIGGER <replaceable class="PARAMETER">name</replaceable> { BEFORE | AFTER | INSTEAD OF } { <replaceable class="PARAMETER">event</replaceable> [ OR ... ] }
     ON <replaceable class="PARAMETER">table_name</replaceable>
     [ FROM <replaceable class="parameter">referenced_table_name</replaceable> ]
-    [ NOT DEFERRABLE | [ DEFERRABLE ] { INITIALLY IMMEDIATE | INITIALLY DEFERRED } ]
+    [ NOT DEFERRABLE | [ DEFERRABLE ] [ INITIALLY IMMEDIATE | INITIALLY DEFERRED ] ]
     [ FOR [ EACH ] { ROW | STATEMENT } ]
     [ WHEN ( <replaceable class="parameter">condition</replaceable> ) ]
     EXECUTE PROCEDURE <replaceable class="PARAMETER">function_name</replaceable> ( <replaceable class="PARAMETER">arguments</replaceable> )