shorter comment

src/db.rs

@@ -1768,8 +1768,7 @@ impl ReadOptions {
         }
     }
 
-    /// Set the upper bound for an iterator, and the upper bound itself
+    /// Set the upper bound for an iterator, and the upper bound itself is not included on the iteration result.
-    /// is not included on the iteration result.
     pub fn set_iterate_upper_bound<K: AsRef<[u8]>>(&mut self, key: K) {
         let key = key.as_ref();
         unsafe {