Doc: fix prompt in psql crosstabview example

The prompt in the crosstabview example was incorrectly indicating
an open parenthesis where there is none in the example query. Fix
by changing to the normal multi-line prompt.

Reported-by: y.saburov@gmail.com
Discussion: https://postgr.es/m/171369707837.684.8207966689229976474@wrigleys.postgresql.org

Author: danielgustafsson

doc/src/sgml/ref/psql-ref.sgml

@@ -5309,9 +5309,9 @@ This second example shows a multiplication table with rows sorted in reverse
 numerical order and columns with an independent, ascending numerical order.
 <programlisting>
 testdb=&gt; <userinput>SELECT t1.first as "A", t2.first+100 AS "B", t1.first*(t2.first+100) as "AxB",</userinput>
-testdb(&gt; <userinput>row_number() over(order by t2.first) AS ord</userinput>
-testdb(&gt; <userinput>FROM my_table t1 CROSS JOIN my_table t2 ORDER BY 1 DESC</userinput>
-testdb(&gt; <userinput>\crosstabview "A" "B" "AxB" ord</userinput>
+testdb-&gt; <userinput>row_number() over(order by t2.first) AS ord</userinput>
+testdb-&gt; <userinput>FROM my_table t1 CROSS JOIN my_table t2 ORDER BY 1 DESC</userinput>
+testdb-&gt; <userinput>\crosstabview "A" "B" "AxB" ord</userinput>
  A | 101 | 102 | 103 | 104
 ---+-----+-----+-----+-----
  4 | 404 | 408 | 412 | 416