bfb4977be9 implement `AsMut<[u8]>` and `AsMut<[u8;4]>` for `Magic` (Noah)
Pull request description:
Follow up to https://github.com/rust-bitcoin/rust-bitcoin/pull/1288#discussion_r982152738
Implemented `AsMut<[u8]>` and `AsMut<[u8;4]>` for `Magic`.
ACKs for top commit:
Kixunil:
ACK bfb4977be9
apoelstra:
ACK bfb4977be9
Tree-SHA512: f1732f2b6db285e64baf07e70917eb8c0938b3a8d11f8266c0f2c846b7b2d4447cb99721b55c9db877f88c398dd74477c41bdae34679b6c3b6ade71455538241