Update files from the datasets library (from 1.6.1)

Release notes: https://github.com/huggingface/datasets/releases/tag/1.6.1

openwebtext.py

@@ -80,7 +80,7 @@ class Openwebtext(datasets.GeneratorBasedBuilder):
         ]
 
     def _generate_examples(self, txt_files):
-        """ Yields examples. """
+        """Yields examples."""
         for idx, filepath in enumerate(txt_files):
             with open(filepath, encoding="utf-8") as f:
                 yield idx, {"text": re.sub("\n\n\n+", "\n\n", f.read()).strip()}