ref-filter: factor out "unrecognized %(foo) arg" errors
Atom parsers that take arguments generally have a catch-all for "this
arg is not recognized". Most of them use the same printf template, which
is good, because it makes life easier for translators. Let's pull this
template into a helper function, which makes the code in the parsers
shorter and avoids any possibility of differences.
As with the previous commit, we'll pick an arbitrary atom to make sure
the test suite covers this code.
Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>