Document i18n for menu macro

templates/widgets.html

@@ -6,6 +6,12 @@ Provide the widget with a content page
 
 {{ widgets::menu(content="_common/menus/main.md") }}
 
+If the content page has a translation, it will be
+automatically loaded in the current language, as long as
+your parent template has a `lang` variable set, like so:
+
+{% set lang = section.lang | default(value=page.lang) %}
+
 Separate entries with a thematic break:
     either ---, ~~~, ___ or <hr />