Rollup merge of rust-lang#31784 - urschrei:chunks_doc, r=steveklabnik

Closes rust-lang#31773

r? @steveklabnik

Author: Manishearth

src/libcollections/slice.rs

@@ -407,7 +407,7 @@ impl<T> [T] {
     }
 
     /// Returns an iterator over `size` elements of the slice at a
-    /// time. The chunks do not overlap. If `size` does not divide the
+    /// time. The chunks are slices and do not overlap. If `size` does not divide the
     /// length of the slice, then the last chunk will not have length
     /// `size`.
     ///
@@ -433,7 +433,7 @@ impl<T> [T] {
     }
 
     /// Returns an iterator over `chunk_size` elements of the slice at a time.
-    /// The chunks are mutable and do not overlap. If `chunk_size` does
+    /// The chunks are mutable slices, and do not overlap. If `chunk_size` does
     /// not divide the length of the slice, then the last chunk will not
     /// have length `chunk_size`.
     ///