docs(retrievers/get-started): Fix broken state_of_the_union.txt link (#7399)

Thank you for this awesome library.

- Description: Fix broken link in documentation 
- Issue:
-
https://python.langchain.com/docs/modules/data_connection/retrievers/#get-started
- the URL:
https://github.com/hwchase17/langchain/blob/master/docs/modules/state_of_the_union.txt
- I think the right one is
https://github.com/hwchase17/langchain/blob/master/docs/extras/modules/state_of_the_union.txt
- Dependencies: -
- Tag maintainer: @baskaryan
- Twitter handle: -

docs/snippets/modules/data_connection/retrievers/get_started.mdx

@@ -66,7 +66,7 @@ from langchain.chains import RetrievalQA
 from langchain.llms import OpenAI
 ```
 
-Next in the generic setup, let's specify the document loader we want to use. You can download the `state_of_the_union.txt` file [here](https://github.com/hwchase17/langchain/blob/master/docs/modules/state_of_the_union.txt)
+Next in the generic setup, let's specify the document loader we want to use. You can download the `state_of_the_union.txt` file [here](https://github.com/hwchase17/langchain/blob/master/docs/extras/modules/state_of_the_union.txt)
 
 
 ```python