Python: Update README.md (#12737)

Update links due to renamed files

### Motivation and Context

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### Contribution Checklist

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---------

Co-authored-by: Evan Mattson <[email protected]>

Author: Nava-7

python/samples/concepts/README.md

@@ -217,8 +217,8 @@
 
 ### RAG - Different ways of `RAG` (Retrieval-Augmented Generation)
 
-- [RAG with Text Memory Plugin](./rag/rag_with_text_memory_plugin.py)
-- [Self-Critique RAG](./rag/self-critique_rag.py)
+- [RAG with Vector Collection](./rag/rag_with_vector_collection.py)
+- [Self-Critique RAG](./rag/self_critique_rag.py)
 
 ### Reasoning - Using [`ChatCompletion`](https://github.com/microsoft/semantic-kernel/blob/main/python/semantic_kernel/connectors/ai/chat_completion_client_base.py) to reason with OpenAI Reasoning