docs: fix notion docs and move to integrations folder

docs/sidebars.js

@@ -136,14 +136,14 @@ module.exports = {
       label: "Integrations",
       collapsed: false,
       items: [
-        "integrations/notion/notion-setup",
-        "integrations/notion/notion-add-content-to-page.md",
-        "integrations/notion/notion-list-database-properties.md",
-        "integrations/notion/notion-list-pages",
-        "integrations/notion/notion-list-users",
-        "integrations/notion/notion-page-content-viewer",
-        "integrations/notion/notion-page-create",
-        "integrations/notion/notion-page-update",
+        "integrations/notion-setup",
+        "integrations/notion-add-content-to-page",
+        "integrations/notion-list-database-properties",
+        "integrations/notion-list-pages",
+        "integrations/notion-list-users",
+        "integrations/notion-page-content-viewer",
+        "integrations/notion-page-create",
+        "integrations/notion-page-update",
       ],
     },
   ],