message: Enable `cargo doc --open` tests on macos.
diff: @@ -1018,7 +1018,7 @@ fn doc_all_member_dependency_same_name() {
  }
  #[cargo_test]
  -#[cfg(not(any(target_os = "windows", target_os = "macos")))]
  +#[cfg(not(windows))] // `echo` may not be available
  fn doc_workspace_open_help_message() {
  let p = project()
  .file(
  @@ -1044,7 +1044,7 @@ fn doc_workspace_open_help_message() {
  }
  #[cargo_test]
  -#[cfg(not(any(target_os = "windows", target_os = "macos")))]
  +#[cfg(not(windows))] // `echo` may not be available
  fn doc_workspace_open_different_library_and_package_names() {
  let p = project()
  .file(
  @@ -1075,7 +1075,7 @@ fn doc_workspace_open_different_library_and_package_names() {
  }
  #[cargo_test]
  -#[cfg(not(any(target_os = "windows", target_os = "macos")))]
  +#[cfg(not(windows))] // `echo` may not be available
  fn doc_workspace_open_binary() {
  let p = project()
  .file(
  @@ -1107,7 +1107,7 @@ fn doc_workspace_open_binary() {
  }
  #[cargo_test]
  -#[cfg(not(any(target_os = "windows", target_os = "macos")))]
  +#[cfg(not(windows))] // `echo` may not be available
  fn doc_workspace_open_binary_and_library() {
  let p = project()
  .file(
  