docs on using vertex tts

docs/my-website/docs/providers/vertex.md

@@ -1812,9 +1812,9 @@ response.stream_to_file(speech_file_path)
 1. Add model to config.yaml
 ```yaml
 model_list:
-  - model_name: multimodalembedding@001
+  - model_name: vertex-tts
     litellm_params:
-      model: vertex_ai/multimodalembedding@001
+      model: vertex_ai/ # Vertex AI does not support passing a `model` param - so passing `model=vertex_ai/` is the only required param
       vertex_project: "adroit-crow-413218"
       vertex_location: "us-central1"
       vertex_credentials: adroit-crow-413218-a956eef1a2a8.json 
@@ -1837,23 +1837,14 @@ import openai
 
 client = openai.OpenAI(api_key="sk-1234", base_url="http://0.0.0.0:4000")
 
-# # request sent to model set on litellm proxy, `litellm --model`
-response = client.embeddings.create(
-    model="multimodalembedding@001", 
-    input = None,
-    extra_body = {
-        "instances": [
-        {
-            "image": {
-                "bytesBase64Encoded": "base64"
-            },
-            "text": "this is a unicorn",
-        },
-    ],
-    }
+# see supported values for "voice" on vertex here: 
+# https://console.cloud.google.com/vertex-ai/generative/speech/text-to-speech
+response = client.audio.speech.create(
+    model = "vertex-tts",
+    input="the quick brown fox jumped over the lazy dogs",
+    voice={'languageCode': 'en-US', 'name': 'en-US-Studio-O'}
 )
-
-print(response)
+print("response from proxy", response)
 ```
 
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