Merge bitcoindevkit/bdk#2405: chore: cargo fmt `crates/core/src/lib.rs`

f97885f8694eca9d72656ba585846bf43378ce25 chore: cargo fmt `crates/core/src/lib.rs` (志宇)

Pull request description:

  ### Description

  Ran `cargo fmt` to fix CI.

  ### Checklists

  #### All Submissions:

  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk/blob/master/CONTRIBUTING.md)

ACKs for top commit:
  Dmenec:
    ACK f97885f8694eca9d72656ba585846bf43378ce25
  noahjoeris:
    ACK f97885f8694eca9d72656ba585846bf43378ce25

Tree-SHA512: 9f493fe5b293f823802a32c5f5bf105bf19d0a7004d8a95135db51def3c6a7ffdbc3a0de5f6dcb28760d2ac77a4b6824ef4e936fc9d011d6bf91328daa0f7505