Small fix

program/localization/en_US/messages.inc

@@ -69,7 +69,7 @@ $messages['keyservererror'] = 'Failed to get key from keyserver.';
 $messages['keyimportsuccess'] = 'Public key $key successfully imported into your keyring.';
 $messages['nocontactsfound'] = 'No contacts found.';
 $messages['contactnotfound'] = 'The requested contact was not found.';
-$messages['contactsearchonly'] = 'You have to use search form to see contacts from the selected addressbook.';
+$messages['contactsearchonly'] = 'You have to use a search form to see contacts from the selected addressbook.';
 $messages['sendingfailed'] = 'Failed to send message.';
 $messages['senttooquickly'] = 'Please wait $sec sec(s). before sending this message.';
 $messages['errorsavingsent'] = 'An error occurred while saving sent message.';