Add some texts to make the tidy check for unsafe documentation pass

diff --git a/library/core/src/slice/mod.rs b/library/core/src/slice/mod.rs
index 8ad3c414454ae68edfe3e18804073f22e8c64483..f511ca8eb7851f207aaa809738fb3683e28231a5 100644 (file)
--- a/library/core/src/slice/mod.rs
+++ b/library/core/src/slice/mod.rs
@@ -559,7 +559,7 @@ pub fn reverse(&mut self) {
             // Use the llvm.bswap intrinsic to reverse u8s in a usize
             let chunk = mem::size_of::<usize>();
             while i + chunk - 1 < ln / 2 {
-                // SAFETY:
+                // SAFETY: There are several things to check here:
                 //
                 // - Note that `chunk` is either 4 or 8 due to the cfg check
                 //   above. So `chunk - 1` is positive.