macro_rules! npgettext {
($msgctxt:expr, $msgid:expr, $msgid_plural:expr, $n:expr, $($args:expr),+ $(,)?) => { ... };
}
Like npgettext, but allows for formatting.
It calls npgettext on msgctxt, msgid, msgid_plural, and n, and then replaces each
occurrence of {} with the next value out of args.