docs: update PgvectorDocumentStore docstring

Co-authored-by: David S. Batista <[email protected]>

integrations/pgvector/src/haystack_integrations/document_stores/pgvector/document_store.py

@@ -131,7 +131,7 @@ def __init__(
             [pgvector documentation](https://github.com/pgvector/pgvector?tab=readme-ov-file#hnsw).
         :param keyword_index_name: Index name for the Keyword index.
         :param connection_param_kwargs: A dictionary of parameters for the PostgreSQL connection.
-            If you prefer not to use the `connection_string`, you can specify connection parameters here.
+            You can specify individual connections parameters here instead of a  `connection_string`
             Common parameters include 'user', 'password', 'host', 'port', & 'dbname'. For a complete list, refer to the
             [PostgreSQL documentation](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-PARAMKEYWORDS).
             Use the `Secret.from_env_var()` method to securely load parameters from environment variables.