Form: rename 'content_below' to 'buttons_extra'

templates/FormView.php

@@ -48,9 +48,9 @@ class FormView extends SubTemplate
 					<div class="offset-sm-2 col-sm-10">
 						<button type="submit" name="submit" class="btn btn-primary">', $this->form->getSubmitButtonCaption(), '</button>';
 
-		if (isset($this->form->content_below))
+		if (isset($this->form->buttons_extra))
 			echo '
-						', $this->form->content_below;
+						', $this->form->buttons_extra;
 
 		echo '
 					</div>