Fix redirect for GitHub.

mkdocs.yml

@@ -25,4 +25,4 @@ plugins:
             - en/sitemap.md
     - redirects:
         redirect_maps:
-            'index.md': 'en/index.md'
\ No newline at end of file
+            'index.md': 'moodle-qtype_stack/en/index.md'
\ No newline at end of file