Re-export ArrayChunksMut in alloc

Author: cuviper

library/alloc/src/slice.rs

@@ -93,6 +93,8 @@ use crate::vec::Vec;
 
 #[unstable(feature = "array_chunks", issue = "74985")]
 pub use core::slice::ArrayChunks;
+#[unstable(feature = "array_chunks", issue = "74985")]
+pub use core::slice::ArrayChunksMut;
 #[stable(feature = "slice_get_slice", since = "1.28.0")]
 pub use core::slice::SliceIndex;
 #[stable(feature = "from_ref", since = "1.28.0")]