code: def expand_all(self):
          
          block = self.editor.document().firstBlock()
          while block.isValid():
              TextBlockHelper.set_collapsed(block, False)
              block.setVisible(True)
              block = block.next()
          self._clear_block_deco()
          self._refresh_editor_and_scrollbars()
          self.expand_all_triggered.emit()
docs: Expands all fold triggers.