message: Removes -Zunstable-options for rustdoc testing
diff: @@ -140,7 +140,6 @@ impl<'cfg> Compilation<'cfg> {
  pub fn rustdoc_process(&self, pkg: &Package, target: &Target) -> CargoResult<ProcessBuilder> {
  let mut p = self.fill_env(process(&*self.config.rustdoc()?), pkg, false)?;
  if target.edition() != Edition::Edition2015 {
  - p.arg("-Zunstable-options");
  p.arg(format!("--edition={}", target.edition()));
  }
  Ok(p)
  