ices/67158.rs: fixed with errors

[github-actions]

Issue: rust-lang/rust#67158

fn main() {
    async { yield print!(":C") };
}

=== stdout ===
=== stderr ===
error[E0658]: yield syntax is experimental
 --> /home/runner/work/glacier/glacier/ices/67158.rs:2:13
  |
2 |     async { yield print!(":C") };
  |             ^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #43122 <https://github.com/rust-lang/rust/issues/43122> for more information
  = help: add `#![feature(generators)]` to the crate attributes to enable

error[E0727]: `async` generators are not yet supported
 --> /home/runner/work/glacier/glacier/ices/67158.rs:2:13
  |
2 |     async { yield print!(":C") };
  |             ^^^^^^^^^^^^^^^^^^

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0658, E0727.
For more information about an error, try `rustc --explain E0658`.
==============