DOC: Typo in example in extract-attachments.md (#2285)

Author: ageitgey

docs/user/extract-attachments.md

@@ -11,7 +11,7 @@ from pypdf import PdfReader
 
 reader = PdfReader("example.pdf")
 
-for name, content_list in reader.attachments:
+for name, content_list in reader.attachments.items():
     for i, content in enumerate(content_list):
         with open(f"{name}-{i}", "wb") as fp:
             fp.write(content)