Given a string "%s foo %s", the gjs JavaScript implementation allows these to be reordered in a fashion similar to C, that is "%2$s foo %1$s". However, `msgfmt -vc' will error on encountering this in a translation when the msgid is marked javascript-format, giving the following:
'msgstr' is not a valid JavaScript format string, unlike 'msgid'. Reason: In the directive number 1, the character '$' is not a valid conversion specifier. javascript-format should be made to understand this form of string formatting, as c-format does. Seán de Búrca
