ices/83921.rs: fixed with errors (#863)

=== stdout ===
=== stderr ===
error[E0552]: incorrect `repr(packed)` attribute format: `packed` takes exactly one parenthesized argument, or no parentheses at all
 --> /home/runner/work/glacier/glacier/ices/83921.rs:2:8
  |
2 | #[repr(packed())]
  |        ^^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0552`.
==============

Co-authored-by: rustbot <rustbot@users.noreply.github.com>