fix docstring

Author: sjrl

integrations/nvidia/src/haystack_integrations/components/embedders/nvidia/document_embedder.py

@@ -248,7 +248,7 @@ def run(self, documents: list[Document]) -> dict[str, Union[list[Document], dict
             - `documents` - List of processed Documents with embeddings.
             - `meta` - Metadata on usage statistics, etc.
         :raises TypeError:
-            If the input is not a string.
+            If the input is not a list of Documents.
         """
         if not self._initialized:
             self.warm_up()