oss(py): rename llm google page (#1756)

Author: mdrxy

src/docs.json

@@ -1845,6 +1845,10 @@
     {
       "source": "/langsmith/agent-server-api-ref",
       "destination": "/langsmith/server-api-ref"
+    },
+    {
+      "source": "/oss/python/integrations/llms/google_ai",
+      "destination": "/oss/python/integrations/llms/google_generative_ai"
     }
   ]
 }

src/oss/python/integrations/chat/google_generative_ai.mdx

@@ -114,6 +114,17 @@ ai_msg
     ```
 </CodeGroup>
 
+<Note>
+    **Message content shape**
+
+    Gemini 3 series models will always return a list of content blocks to capture [thought signatures](#thought-signatures). Use the `.text` property to recover string content.
+
+    ```python
+    response.content  # -> [{"type": "text", "text": "Hello!", "extras": {"signature": "EpQFCp...lKx64r"}}]
+    response.text     # -> "Hello!"
+    ```
+</Note>
+
 ```python
 print(ai_msg.content)
 ```
@@ -130,17 +141,6 @@ print(ai_msg.content)
     ```
 </CodeGroup>
 
-<Note>
-    **Message content shape**
-
-    Gemini 3 series models will always return a list of content blocks to capture [thought signatures](#thought-signatures). Use the `.text` property to recover string content.
-
-    ```python
-    response.content  # -> [{"type": "text", "text": "Hello!", "extras": {"signature": "EpQFCp...lKx64r"}}]
-    response.text     # -> "Hello!"
-    ```
-</Note>
-
 ## Multimodal usage
 
 Gemini models can accept multimodal inputs (text, images, audio, video) and, for some models, generate multimodal outputs.
@@ -418,6 +418,14 @@ Certain models (such as `gemini-2.5-flash-preview-tts`) can generate audio files
 
 See more information on the [Gemini API docs](https://ai.google.dev/gemini-api/docs/speech-generation) for details.
 
+<Warning>
+    **Vertex AI Limitation**
+
+    Audio generation models are currently in limited preview on Vertex AI and may require allowlist access. If you encounter an `INVALID_ARGUMENT` error when using TTS models with `vertexai=True`, your GCP project may need to be allowlisted.
+
+    For more details, see this [Google AI forum discussion](https://discuss.ai.google.dev/t/request-allowlist-access-for-audio-output-in-gemini-2-5-pro-flash-tts-vertex-ai/108067).
+</Warning>
+
 ```python
 from langchain_google_genai import ChatGoogleGenerativeAI, Modality
 

…s/python/integrations/llms/google_ai.mdx …tegrations/llms/google_generative_ai.mdxsrc/oss/python/integrations/llms/google_ai.mdx renamed to src/oss/python/integrations/llms/google_generative_ai.mdx src/oss/python/integrations/llms/google_ai.mdx renamed to src/oss/python/integrations/llms/google_generative_ai.mdx

@@ -1,5 +1,6 @@
 ---
-title: Google AI
+title: GoogleGenerativeAI
+description: Get started using legacy Gemini LLMs in LangChain.
 ---
 
 <Warning>