simple -> simply (#1919)

docs/docs/tutorials/rag/langgraph_agentic_rag.ipynb

@@ -9,7 +9,7 @@
     "\n",
     "[Retrieval Agents](https://python.langchain.com/docs/tutorials/qa_chat_history/#agents) are useful when we want to make decisions about whether to retrieve from an index.\n",
     "\n",
-    "To implement a retrieval agent, we simple need to give an LLM access to a retriever tool.\n",
+    "To implement a retrieval agent, we simply need to give an LLM access to a retriever tool.\n",
     "\n",
     "We can incorporate this into [LangGraph](https://langchain-ai.github.io/langgraph/).\n",
     "\n",