Message extraction: is there a convention for no-op ngettext alias?

[Pedro Romano]

When marking strings for translation 'N_' is convention used as the no-op 'gettext' alias, and the Babel message extractor properly recognises it.

Is there any such convention for a no-op alias for 'ngettext' (for singular and plural forms)? The message extractor needs a little tweaking to recognise strings with singular and plural forms marked for translation and I would like to propose a patch that would follow the accepted convention.

Thanks for any feedback regarding this issue.
--Pedro.