Minor `LLMChain` docs correction (#3791)

`LLMChain` run method can take multiple input variables.

docs/modules/chains/generic/llm_chain.ipynb

@@ -137,13 +137,12 @@
    ]
   },
   {
+   "attachments": {},
    "cell_type": "markdown",
    "id": "a178173b-b183-432a-a517-250fe3191173",
    "metadata": {},
    "source": [
-    "- `predict` is similar to `run` method except in 2 ways:\n",
-    "    - Input key is specified as keyword argument instead of a Python dict\n",
-    "    - It supports multiple input keys."
+    "- `predict` is similar to `run` method except that the input keys are specified as keyword arguments instead of a Python dict."
    ]
   },
   {