message: Remove sub-expressions for InvalidClassEscape
diff: @@ -1574,9 +1574,8 @@ impl fmt::Display for ErrorKind {
  write!(f, "Invalid character class range '{}-{}'. \
  Character class ranges must start with the smaller \
  character, but {} > {}", start, end, start, end),
  - InvalidClassEscape(ref e) =>
  - write!(f, "Invalid escape sequence in character \
  - class: '{}'.", e),
  + InvalidClassEscape(_) =>
  + write!(f, "Invalid escape sequence in character class."),
  InvalidRepeatRange { min, max } =>
  write!(f, "Invalid counted repetition range: {{{}, {}}}. \
  Counted repetition ranges must start with the \
  