Function deltachat::simplify::remove_nonstandard_footer

fn remove_nonstandard_footer<'a>(lines: &'a [&str]) -> (&'a [&'a str], bool)

Remove nonstandard footer and a boolean indicating whether such footer was removed. Returns (lines, is_footer_removed) tuple; is_footer_removed is set to true if the footer was actually removed from lines (which is equal to the input array otherwise).