Update to nightly rust v1.63.0 breaks breaks cargo test

[jakerumbles]

Ran rustup update yesterday. Running openbrush contract unit tests worked fine before I updated, running RUSTFLAGS="-D warnings" cargo +nightly test --all-features --workspace -- --test-threads=10, but now it fails to compile due to #[doc(hidden)] is ignored on trait impl items

I was told by OpenBrush team that ink! adds #[doc(hidden)], so hopefully I have created this issue in the right place.

I'll try to revert my nightly version for now, but it looks like this will break things in the future.