Merge rust-bitcoin/rust-bitcoin#6269: internals: regenerate api snapshots

27aa84e31aa94dfc11d32c8cabb4874516702d86 internals: regenerate api snapshots for ArrayVec (satsfy (Renato Britto))

Pull request description:

  Closes https://github.com/rust-bitcoin/rust-bitcoin/issues/6268
  
  The api snapshot files were not refreshed when `ArrayVec::set_len` and `ArrayVec::spare_capacity_mut` were added, leaving `cargo rbmt api` failing on master and on every PR that branches from it.
  
  Running `cargo rbmt api` on the pinned nightly toolchain regenerates the three `internals/api/*.txt files`, fixing the drift.


ACKs for top commit:
  apoelstra:
    ACK 27aa84e31aa94dfc11d32c8cabb4874516702d86; successfully ran local tests


Tree-SHA512: d7eb5b9d35fa32bec91430862d04e5fc179e5c2bea3895ab01ae2bd4d5adadad12b8c0cac236c12b59bb9ea9e2a781878a7fcb5764f661b05831b441508bd74e