DOCS: doc-string - langchain.vectorstores.dashvector.DashVector (#13502)

- **Description:** There are several mistakes in the sample code in the
doc-string of `DashVector` class, and this pull request aims to correct
them.
The correction code has been tested against latest version (at the time
of creation of this pull request) of: `langchain==0.0.336`
`dashvector==1.0.6` .
- **Issue:** No issue is created for this.
- **Dependencies:** No dependency is required for this change,
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- **Twitter handle:** `zeyanglin`

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libs/langchain/langchain/vectorstores/dashvector.py

@@ -29,15 +29,15 @@ class DashVector(VectorStore):
     Example:
         .. code-block:: python
 
-            from langchain.vectorstores import dashvector
+            from langchain.vectorstores import DashVector
             from langchain.embeddings.openai import OpenAIEmbeddings
             import dashvector
 
-            client = dashvector.Client.init(api_key="***")
-            client.create("langchain")
+            client = dashvector.Client(api_key="***")
+            client.create("langchain", dimension=1024)
             collection = client.get("langchain")
             embeddings = OpenAIEmbeddings()
-            vectorstore = Dashvector(collection, embeddings.embed_query, "text")
+            vectorstore = DashVector(collection, embeddings.embed_query, "text")
     """
 
     def __init__(