docs: Update VectorStore .as_retriever method url in vectorstore_retr…

…iever.ipynb (langchain-ai#27842)

**Description**: Update VectorStore `.as_retriever` method url in
`vectorstore_retriever.ipynb`

Co-authored-by: Erick Friis <[email protected]>

docs/docs/how_to/vectorstore_retriever.ipynb

@@ -28,7 +28,7 @@
     "\n",
     "## Creating a retriever from a vectorstore\n",
     "\n",
-    "You can build a retriever from a vectorstore using its [.as_retriever](https://python.langchain.com/api_reference/core/vectorstores/langchain_core.vectorstores.VectorStore.html#langchain_core.vectorstores.VectorStore.as_retriever) method. Let's walk through an example.\n",
+    "You can build a retriever from a vectorstore using its [.as_retriever](https://python.langchain.com/api_reference/core/vectorstores/langchain_core.vectorstores.base.VectorStore.html#langchain_core.vectorstores.base.VectorStore.as_retriever) method. Let's walk through an example.\n",
     "\n",
     "First we instantiate a vectorstore. We will use an in-memory [FAISS](https://python.langchain.com/api_reference/community/vectorstores/langchain_community.vectorstores.faiss.FAISS.html) vectorstore:"
    ]