doc: Remove claim about large shared_buffers on Windows

Testing has shown that it is no longer correct.

From: Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com>
Reviewed-by: amul sul <sulamul@gmail.com>
Discussion: http://www.postgresql.org/message-id/flat/0A3221C70F24FB45833433255569204D1F5EE995@G01JPEXMBYT05/

doc/src/sgml/config.sgml

@@ -1316,11 +1316,6 @@ include_dir 'conf.d'
        <para>
         On systems with less than 1GB of RAM, a smaller percentage of RAM is
         appropriate, so as to leave adequate space for the operating system.
-        Also, on Windows, large values for <varname>shared_buffers</varname>
-        aren't as effective.  You may find better results keeping the setting
-        relatively low and using the operating system cache more instead.  The
-        useful range for <varname>shared_buffers</varname> on Windows systems
-        is generally from 64MB to 512MB.
        </para>
 
       </listitem>