message: Improve wording of safety comment
diff: @@ -159,19 +159,17 @@ impl<Entry> std::ops::Deref for UniqueEnv<Entry> {
  type Target = SliceEnv<Entry>;
  fn deref(&self) -> &SliceEnv<Entry> {
  - // SAFTEY:
  - // - `SliceEnv<Entry>` and `[Entry]` have the same in-memory,
  - // so the `transmute` should be safe.
  - unsafe { std::mem::transmute(&self.entries[..]) }
  + // SAFETY:
  + // - `SliceEnv<Entry>` is equivalent to a `[Entry]` internally
  + unsafe { std::mem::transmute::<&[_], &SliceEnv<_>>(&self.entries[..]) }
  }
  }
  impl<Entry> std::ops::DerefMut for UniqueEnv<Entry> {
  fn deref_mut(&mut self) -> &mut SliceEnv<Entry> {
  - // SAFTEY:
  - // - `SliceEnv<Entry>` and `[Entry]` have the same in-memory,
  - // so the `transmute` should be safe.
  - unsafe { std::mem::transmute(&mut self.entries[..]) }
  + // SAFETY:
  + // - `SliceEnv<Entry>` is equivalent to a `[Entry]` internally
  + unsafe { std::mem::transmute::<&mut [_], &mut SliceEnv<_>>(&mut self.entries[..]) }
  }
  }
  