fix bug

Author: TsinghuaLucky912

postgresql/doc/src/sgml/query.sgml

@@ -1398,7 +1398,7 @@ SELECT city, count(*) FILTER (WHERE temp_lo < 45), max(temp_lo)
 
 <screen>
      city      | count | max
----------------+-------+-----
+-&minus;-&minus;-&minus;-&minus;-+-&minus;-&minus;-&minus;-&minus;-+-&minus;-&minus;-
  Hayward       |     1 |  37
  San Francisco |     1 |  46
 (2 rows)