Updated comment.

modules/Migration/schema/640_to_650.php

@@ -55,7 +55,7 @@ $adb->pquery("Update vtiger_settings_field set linkto='index.php?parent=Settings
 $adb->pquery("Update vtiger_settings_field set linkto='index.php?module=Workflows&parent=Settings&view=List' where name='LBL_LIST_WORKFLOWS'", array());
 $adb->pquery("Update vtiger_settings_field set linkto='index.php?module=Vtiger&parent=Settings&view=ConfigEditorDetail' where name='LBL_CONFIG_EDITOR'", array());
 
-//allow large emails to be stored.
+// Extend description data-type (eg. allow large emails to be stored)
 $adb->pquery("ALTER TABLE vtiger_crmentity MODIFY COLUMN description MEDIUMTEXT", array());
 
 }