Make Clippy happy.

src/tests/mod.rs

@@ -13,7 +13,7 @@ pub mod postprocessor;
 mod stdlib;
 mod validity;
 
-const SUCCEEDED: &'static str = "Succeeded";
+const SUCCEEDED: &str = "Succeeded";
 
 /// Compare the output of the given code with the expected output.
 pub fn test_amber(code: impl Into<String>, expected: &str) {