Rollup merge of rust-lang#86101 - glittershark:bound-as-mut-doc-fix, …

…r=m-ou-se

Correct type signature in doc for Bound::as_mut

Thanks to `@drmason13` for pointing this out!

library/core/src/ops/range.rs

@@ -686,7 +686,7 @@ impl<T> Bound<T> {
  }
  }
 
- /// Converts from `&mut Bound<T>` to `Bound<&T>`.
+ /// Converts from `&mut Bound<T>` to `Bound<&mut T>`.
  #[inline]
  #[unstable(feature = "bound_as_ref", issue = "80996")]
  pub fn as_mut(&mut self) -> Bound<&mut T> {