update config template

config.php-dist

@@ -30,6 +30,8 @@
 	define('ICONS_DIR', "icons");
 	define('ICONS_URL', "icons");
 	// Local and URL path to the directory, where feed favicons are stored.
+	// Unless you really know what you're doing, please keep those relative
+	// to tt-rss main directory.
 
 	define('SINGLE_USER_MODE', true);
 	// Operate in single user mode, disables all functionality related to