docs: (#8464)

Author: hntrl

docs/core_docs/docs/tutorials/graph.ipynb

@@ -86,7 +86,7 @@
     },
     {
       "cell_type": "code",
-      "execution_count": 3,
+      "execution_count": null,
       "metadata": {},
       "outputs": [
         {
@@ -112,7 +112,7 @@
         "import { Neo4jGraph } from \"@langchain/community/graphs/neo4j_graph\";\n",
         "\n",
         "const url = process.env.NEO4J_URI;\n",
-        "const username = process.env.NEO4J_USER;\n",
+        "const username = process.env.NEO4J_USERNAME;\n",
         "const password = process.env.NEO4J_PASSWORD;\n",
         "const graph = await Neo4jGraph.initialize({ url, username, password });\n",
         "\n",