community[patch]: FAISS: ValueError mentions normalize_score_fn isnte…

…ad of relevance_score_fn (langchain-ai#25225)

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- [X] **PR title**: "community: fix valueerror mentions wrong argument
missing"
- Where "package" is whichever of langchain, community, core,
experimental, etc. is being modified. Use "docs: ..." for purely docs
changes, "templates: ..." for template changes, "infra: ..." for CI
changes.
  - Example: "community: add foobar LLM"


- [X] **PR message**: ***Delete this entire checklist*** and replace
with
- **Description:** when faiss.py has a None relevance_score_fn it raises
a ValueError that says a normalize_fn_score argument is needed.

Co-authored-by: ccurme <[email protected]>

libs/community/langchain_community/vectorstores/faiss.py

@@ -1288,7 +1288,7 @@ def _similarity_search_with_relevance_scores(
         relevance_score_fn = self._select_relevance_score_fn()
         if relevance_score_fn is None:
             raise ValueError(
-                "normalize_score_fn must be provided to"
+                "relevance_score_fn must be provided to"
                 " FAISS constructor to normalize scores"
             )
         docs_and_scores = self.similarity_search_with_score(
@@ -1317,7 +1317,7 @@ async def _asimilarity_search_with_relevance_scores(
         relevance_score_fn = self._select_relevance_score_fn()
         if relevance_score_fn is None:
             raise ValueError(
-                "normalize_score_fn must be provided to"
+                "relevance_score_fn must be provided to"
                 " FAISS constructor to normalize scores"
             )
         docs_and_scores = await self.asimilarity_search_with_score(