chore(docs): bump langgraph in docs & reformat all docs (#32044)

Trying to unblock documentation build pipeline

* Bump langgraph dep in docs
* Update langgraph in lock file (resolves an issue in API reference
generation)

docs/scripts/arxiv_references.py

@@ -608,7 +608,7 @@ From the opposite direction, scientists use `LangChain` in research and referenc
                 f"""
 ## {paper.title}
 
-- **Authors:** {', '.join(paper.authors)}
+- **Authors:** {", ".join(paper.authors)}
 - **arXiv id:** [{paper.arxiv_id}]({paper.url})  **Published Date:** {paper.published_date}
 - **LangChain:**
 

docs/scripts/check_imports.py

@@ -128,4 +128,4 @@ def check_notebooks(directory: str) -> list:
 if __name__ == "__main__":
     bad_files = check_notebooks(DOCS_DIR)
     if bad_files:
-        raise ImportError("Found bad imports:\n" f"{_serialize_bad_imports(bad_files)}")
+        raise ImportError(f"Found bad imports:\n{_serialize_bad_imports(bad_files)}")