message: Mark proc-macro crates
diff: @@ -66,7 +66,18 @@ impl<'a> fmt::Display for Display<'a> {
  match chunk {
  Chunk::Raw(s) => fmt.write_str(s)?,
  Chunk::Package => {
  - write!(fmt, "{} v{}", package.name(), package.version())?;
  + let proc_macro_suffix = if package.proc_macro() {
  + " (proc-macro)"
  + } else {
  + ""
  + };
  + write!(
  + fmt,
  + "{} v{}{}",
  + package.name(),
  + package.version(),
  + proc_macro_suffix
  + )?;
  let source_id = package.package_id().source_id();
  if !source_id.is_default_registry() {
  