added info for style.local.ini files

style.ini

@@ -1,6 +1,11 @@
 ; Please see http://www.php.net/manual/en/function.parse-ini-file.php
 ; for limitations of the ini format used here
 
+; To extend this file or make changes to it, it is recommended to create
+; a style.local.ini file to prevent losing any changes after an upgrade.
+; Please don't forget to copy the section your changes should be under
+; (i.e. [stylesheets] or [replacements]) into that file as well.
+
 ; Define the stylesheets your template uses here. The second value
 ; defines for which output media the style should be loaded. Currently
 ; print, screen and all are supported.