Remove non-breaking spaces (#20929)

* Remove non-breaking space in comment

It was likely added unintionally.

* Remove remaining non-breaking spaces

examples/research_projects/seq2seq-distillation/README.md

@@ -188,18 +188,18 @@ Some of them are metrics, some of them are checkpoints, some of them are metadat
 ```bash
 output_dir
 ├── best_tfmr  # this is a huggingface checkpoint generated by save_pretrained. It is the same model as the PL .ckpt file below
-│   ├── config.json
-│   ├── merges.txt
-│   ├── pytorch_model.bin
-│   ├── special_tokens_map.json
-│   ├── tokenizer_config.json
-│   └── vocab.json
+│   ├── config.json
+│   ├── merges.txt
+│   ├── pytorch_model.bin
+│   ├── special_tokens_map.json
+│   ├── tokenizer_config.json
+│   └── vocab.json
 ├── git_log.json   # repo, branch, and commit hash
 ├── val_avg_rouge2=0.1984-step_count=11.ckpt  # this is a pytorch lightning checkpoint associated with the best val score. (it will be called BLEU for MT)
 ├── metrics.json  # new validation metrics will continually be appended to this
 ├── student  # this is a huggingface checkpoint generated by SummarizationDistiller. It is the student before it gets finetuned.
-│   ├── config.json
-│   └── pytorch_model.bin
+│   ├── config.json
+│   └── pytorch_model.bin
 ├── test_generations.txt
 # ^^ are the summaries or translations produced by your best checkpoint on the test data. Populated when training is done
 ├── test_results.txt  # a convenience file with the test set metrics. This data is also in metrics.json['test']