message: Print correct platform line ending around truncation message
diff: @@ -4,9 +4,11 @@ use std::fmt;
  use std::fs::{File, OpenOptions};
  use std::io::{self, Read, Write};
  +use crate::util::LINE_ENDING;
  +
  const SHORT_OUTPUT_LENGTH: usize = 20 * 80;
  const TRUNCATED_TTY_MSG: &[u8] =
  - b"\n[truncated; use a pipe, a redirect, or --output to see full message]\n";
  + b"[truncated; use a pipe, a redirect, or -o/--output to see full message]";
  #[derive(Debug)]
  struct DenyBinaryOutputError;
  @@ -118,7 +120,9 @@ impl Write for StdoutWriter {
  // Drop output if we've truncated already, or need to.
  if self.truncated || self.count == SHORT_OUTPUT_LENGTH {
  if !self.truncated {
  + self.inner.write_all(LINE_ENDING.as_bytes())?;
  self.inner.write_all(TRUNCATED_TTY_MSG)?;
  + self.inner.write_all(LINE_ENDING.as_bytes())?;
  self.truncated = true;
  }
  @@ -142,7 +146,9 @@ impl Write for StdoutWriter {
  // truncate and drop the remainder.
  if self.count == SHORT_OUTPUT_LENGTH && data.len() > to_write {
  if !self.truncated {
  + self.inner.write_all(LINE_ENDING.as_bytes())?;
  self.inner.write_all(TRUNCATED_TTY_MSG)?;
  + self.inner.write_all(LINE_ENDING.as_bytes())?;
  self.truncated = true;
  }
  ret += io::sink().write(&data[to_write..])?;
  