message: docs(Z-flags): Add description for each -Z flag in cargo -Z help
diff: @@ -10,6 +10,24 @@ use command_prelude::*;
  pub fn main(config: &mut Config) -> CliResult {
  let args = cli().get_matches_safe()?;
  +
  + if args.value_of("unstable-features") == Some("help") {
  + println!(
  + "
  +Available unstable (nightly-only) flags:
  +
  + -Z avoid-dev-deps -- Avoid installing dev-dependencies if possible
  + -Z minimal-versions -- Install minimal dependency versions instead of maximum
  + -Z no-index-update -- Do not update the registry, avoids a network request for benchmarking
  + -Z offline -- Offline mode that does not perform network requests
  + -Z print-im-a-teapot -- Example option for demonstration purposes
  + -Z unstable-options -- Allow the usage of unstable options such as --registry
  +
  +Run with 'cargo -Z [FLAG] [SUBCOMMAND]'"
  + );
  + return Ok(());
  + }
  +
  let is_verbose = args.occurrences_of("verbose") > 0;
  if args.is_present("version") {
  let version = cargo::version();
  @@ -161,7 +179,7 @@ See 'cargo help <command>' for more information on a specific command.\n",
  .arg(opt("locked", "Require Cargo.lock is up to date").global(true))
  .arg(
  Arg::with_name("unstable-features")
  - .help("Unstable (nightly-only) flags to Cargo")
  + .help("Unstable (nightly-only) flags to Cargo, see 'cargo -Z help' for details")
  .short("Z")
  .value_name("FLAG")
  .multiple(true)
  