patch: deprecate (a)get_relevant_documents (#20477)

- `.get_relevant_documents(query)` -> `.invoke(query)`
- `.get_relevant_documents(query=query)` -> `.invoke(query)`
- `.get_relevant_documents(query, callbacks=callbacks)` ->
`.invoke(query, config={"callbacks": callbacks})`
- `.get_relevant_documents(query, **kwargs)` -> `.invoke(query,
**kwargs)`

---------

Co-authored-by: Erick Friis <erick@langchain.dev>

libs/community/langchain_community/retrievers/milvus.py

@@ -59,7 +59,7 @@ class MilvusRetriever(BaseRetriever):
         run_manager: CallbackManagerForRetrieverRun,
         **kwargs: Any,
     ) -> List[Document]:
-        return self.retriever.get_relevant_documents(
+        return self.retriever.invoke(
             query, run_manager=run_manager.get_child(), **kwargs
         )