fixup! erp5_web_renderjs_ui: let gadget know the language in which the interface is rendered

bt5/erp5_web_renderjs_ui/PathTemplateItem/web_page_module/rjs_interface_translation.html

@@ -8,6 +8,13 @@
     <h3>Gadget used to translate text</h3>
     <dl>
 
+      <dt>getSelectedLanguage</dt>
+      <dd>Return the selected language, in which the UI is displayed</dd>
+      <dl>
+        <dt data-parameter-required="required">text</dt>
+        <dd></dd>
+      </dl>
+
       <dt>translate</dt>
       <dd>Translate a text</dd>
       <dl>