message: Remove whole crate import
diff: //! Adapted from `sha2` [sha256.rs](https://github.com/RustCrypto/hashes/blob/master/sha2/src/sha256.rs)
  use sha2::digest::consts::U32;
  use sha2::digest::generic_array::GenericArray;
  -use sha2::digest::{FixedOutputDirty, Reset, Update};
  -
  -use sha2::digest;
  +use sha2::digest::{FixedOutputDirty, Output, Reset, Update};
  /// The 256-bits identity container
  #[derive(Clone)]
  @@ -33,7 +31,7 @@ impl Update for Identity256 {
  impl FixedOutputDirty for Identity256 {
  type OutputSize = U32;
  - fn finalize_into_dirty(&mut self, out: &mut digest::Output<Self>) {
  + fn finalize_into_dirty(&mut self, out: &mut Output<Self>) {
  *out = self.array;
  }
  }
  