Use new types syntax

Author: lucic71

rules/dirent/tgt_unsafe.rs

@@ -1,9 +1,8 @@
 // Copyright (c) 2022-present INESC-ID.
 // Distributed under the MIT license that can be found in the LICENSE file.
 
-fn types() -> Result<(), Box<dyn std::error::Error>> {
-    let t1: *mut ::libc::DIR = std::ptr::null_mut();
-    Ok(())
+fn t1() -> *mut ::libc::DIR {
+    std::ptr::null_mut()
 }
 
 unsafe fn f1(a0: *const u8) -> *mut ::libc::DIR {