ices/51173.rs: fixed with errors

=== stdout ===
=== stderr ===
error: unexpected token: `("bug")`
 --> /home/runner/work/glacier/glacier/ices/51173.rs:2:32
  |
2 |     ( $doc:expr ) => { #[doc = $doc] enum Bug {} }
  |                                ^^^^
...
5 | bug! { (stringify!(bug)) }
  | -------------------------- in this macro invocation
  |
  = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to previous error

==============

Author: rustbot