message: Fix doc comment wording
diff: @@ -175,7 +175,7 @@ impl<Entry> std::ops::Deref for UniqueEnv<Entry> {
  fn deref(&self) -> &SliceEnv<Entry> {
  // SAFETY:
  - // - `SliceEnv<Entry>` is equivalent to a `[Entry]` internally
  + // - `SliceEnv<Entry>` is equivalent to an `[Entry]` internally
  unsafe { std::mem::transmute::<&[_], &SliceEnv<_>>(&self.entries[..]) }
  }
  }
  @@ -183,7 +183,7 @@ impl<Entry> std::ops::Deref for UniqueEnv<Entry> {
  impl<Entry> std::ops::DerefMut for UniqueEnv<Entry> {
  fn deref_mut(&mut self) -> &mut SliceEnv<Entry> {
  // SAFETY:
  - // - `SliceEnv<Entry>` is equivalent to a `[Entry]` internally
  + // - `SliceEnv<Entry>` is equivalent to an `[Entry]` internally
  unsafe { std::mem::transmute::<&mut [_], &mut SliceEnv<_>>(&mut self.entries[..]) }
  }
  }
  