📖 docs: fixed integrations/document loaders toc (#9281)

Fixed navbar:
- renamed several files, so ToC is sorted correctly
- made ToC items consistent: formatted several Titles
- added several links
- reformatted several docs to a consistent format
- renamed several files (removed `_example` suffix)
- added renamed files to the `docs/docs_skeleton/vercel.json`

docs/extras/integrations/document_loaders/async_html.ipynb

@@ -5,9 +5,9 @@
    "id": "e229e34c",
    "metadata": {},
    "source": [
-    "# AsyncHtmlLoader\n",
+    "# AsyncHtml\n",
     "\n",
-    "AsyncHtmlLoader loads raw HTML from a list of urls concurrently."
+    "`AsyncHtmlLoader` loads raw HTML from a list of URLs concurrently."
    ]
   },
   {
@@ -99,7 +99,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.9.16"
+   "version": "3.10.12"
   }
  },
  "nbformat": 4,