Handle convention changes.

def setup_docstring_style_convention(self, text):
        """Handle convention changes."""
        if text == 'Custom':
            self.docstring_style_select.label.setText(
                _("Show the following errors:"))
            self.docstring_style_ignore.label.setText(
                _("Ignore the following errors:"))
        else:
            self.docstring_style_select.label.setText(
                _("Show the following errors in addition "
                  "to the specified convention:"))
            self.docstring_style_ignore.label.setText(
                _("Ignore the following errors in addition "
                  "to the specified convention:"))