Mv LCEL routing doc (#10713)

Move to how-to

docs/docs_skeleton/vercel.json

@@ -1,5 +1,9 @@
 {
   "redirects": [
+    {
+      "source": "/docs/expression_language/cookbook/routing",
+      "destination": "/docs/expression_language/how_to/routing"
+    },
     {
       "source":  "/docs/integrations/providers/amazon_api_gateway",
       "destination": "/docs/integrations/platform/aws"

docs/extras/expression_language/how_to/routing.ipynb

@@ -5,7 +5,7 @@
    "id": "4b47436a",
    "metadata": {},
    "source": [
-    "# Routing\n",
+    "# Route between multiple Runnables\n",
     "\n",
     "This notebook covers how to do routing in the LangChain Expression Language\n",
     "\n",
@@ -224,7 +224,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.10.1"
+   "version": "3.9.1"
   }
  },
  "nbformat": 4,