transformers

a5c05e31 - Fix remaining RAG doc examples that crash on current transformers (#46044)

Fix remaining RAG doc examples that crash on current transformers (#46044) Fix RAG documentation examples that crash on current transformers - Use `facebook/rag-sequence-nq` instead of `facebook/dpr-ctx_encoder-single-nq-base` for `RagRetriever.from_pretrained()`. The DPR checkpoint lacks the `question_encoder` and `generator` sub-configs that `RagConfig` requires, causing a `ValueError` on construction. - Replace removed `tokenizer.prepare_seq2seq_batch()` with `tokenizer()` in the doc page examples. - Use consistent `facebook/rag-sequence-nq` checkpoint for `RagSequenceForGeneration` instead of `facebook/rag-token-nq`. closes: #46015