message: Removing `err.description()` before deprecation.
diff: @@ -239,7 +239,6 @@ mod tests {
  use crate::directory::TerminatingWrite;
  use byteorder::{ByteOrder, LittleEndian};
  use regex::Regex;
  - use std::error::Error;
  use std::io;
  #[test]
  @@ -362,7 +361,7 @@ mod tests {
  let err = Footer::deserialize(&mut &buf[..]).unwrap_err();
  assert_eq!(err.kind(), io::ErrorKind::InvalidData);
  assert_eq!(
  - err.description(),
  + err.to_string(),
  "Footer seems invalid as it suggests a footer len of 10001. File is corrupted, \
  or the index was created with a different & old version of tantivy."
  );
  