add crate::kani

Author: thanhnguyen-aws

library/core/src/slice/memchr.rs

@@ -167,7 +167,8 @@ pub fn memrchr(x: u8, text: &[u8]) -> Option<usize> {
 #[unstable(feature = "kani", issue = "none")]
 pub mod verify {
     use super::*;
-
+    use crate::kani;
+    
     #[kani::proof]
     #[cfg(not(all(target_arch = "x86_64", target_feature = "sse2")))]
     pub fn check_memchr_naive() {