Add prompt hub for various use-cases (#9879)

Use prompt hub in our use-case docs and guides.

docs/extras/use_cases/sql.ipynb

@@ -149,9 +149,7 @@
   {
    "cell_type": "code",
    "execution_count": 8,
-   "metadata": {
-    "scrolled": false
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "from langchain.chat_models import ChatOpenAI\n",
@@ -251,7 +249,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 11,
+   "execution_count": 1,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -280,6 +278,25 @@
     ")"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "We can also access this [prompt](https://smith.langchain.com/hub/rlm/text-to-sql) in the LangChain prompt hub.\n",
+    "\n",
+    "This will work with your [LangSmith API key](https://docs.smith.langchain.com/)."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from langchain import hub\n",
+    "CUSTOM_PROMPT = hub.pull(\"rlm/text-to-sql\")"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -854,5 +871,5 @@
   }
  },
  "nbformat": 4,
- "nbformat_minor": 2
+ "nbformat_minor": 4
 }