Fix clippy warnings (#1168)

cranelift/src/cat.rs

@@ -8,7 +8,7 @@ use crate::CommandResult;
 use cranelift_reader::parse_functions;
 
 pub fn run(files: &[String]) -> CommandResult {
-    for (i, f) in files.into_iter().enumerate() {
+    for (i, f) in files.iter().enumerate() {
         if i != 0 {
             println!();
         }