[feature/twig] INCLUDEJS now uses the definition class

This had to be done because, like DEFINE, setting variables to $context
only affected the local file and any children, not parent templates.

PHPBB3-11598

phpBB/styles/prosilver/template/overall_footer.html

@@ -56,7 +56,7 @@
 <script type="text/javascript" src="{T_SUPER_TEMPLATE_PATH}/forum_fn.js?assets_version={T_ASSETS_VERSION}"></script>
 <script type="text/javascript" src="{T_ASSETS_PATH}/javascript/core.js?assets_version={T_ASSETS_VERSION}"></script>
 <!-- INCLUDEJS {T_TEMPLATE_PATH}/ajax.js -->
-{SCRIPTS}
+{$SCRIPTS}
 
 <!-- EVENT overall_footer_after -->
 </body>