ices/63300.rs: fixed with errors

[github-actions]

Issue: rust-lang/rust#63300

trait Functor<A> {
    type HigherSelf<T>: Functor<T>;
}

=== stdout ===
=== stderr ===
error[E0658]: generic associated types are unstable
 --> /home/runner/work/glacier/glacier/ices/63300.rs:2:5
  |
2 |     type HigherSelf<T>: Functor<T>;
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: for more information, see https://github.com/rust-lang/rust/issues/44265
  = help: add `#![feature(generic_associated_types)]` to the crate attributes to enable

error[E0601]: `main` function not found in crate `63300`
 --> /home/runner/work/glacier/glacier/ices/63300.rs:1:1
  |
1 | / trait Functor<A> {
2 | |     type HigherSelf<T>: Functor<T>;
3 | | }
  | |_^ consider adding a `main` function to `/home/runner/work/glacier/glacier/ices/63300.rs`

error: type-generic associated types are not yet implemented
 --> /home/runner/work/glacier/glacier/ices/63300.rs:2:5
  |
2 |     type HigherSelf<T>: Functor<T>;
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: for more information, see https://github.com/rust-lang/rust/issues/44265

error: aborting due to 3 previous errors

Some errors have detailed explanations: E0601, E0658.
For more information about an error, try `rustc --explain E0601`.
==============