docs: fixed typo in v2 example v2 (#378)

Update v2.md - fixed typo in example: iterate_items -> iterate_items()

Signed-off-by: Gaspard Petit <[email protected]>

docs/v2.md

@@ -152,7 +152,7 @@ conv_result: ConversionResult = doc_converter.convert("https://arxiv.org/pdf/240
 conv_result.document.print_element_tree()
 
 ## Iterate the elements in reading order, including hierachy level:
-for item, level in conv_result.document.iterate_items:
+for item, level in conv_result.document.iterate_items():
     if isinstance(item, TextItem):
         print(item.text)
     elif isinstance(item, TableItem):