tests ~ fix cargo clippy complaint (*allow* clippy::manual_strip; with FixME/ToDO)

- replace with the included/noted code when MSRV includes a stabilized `String::strip_prefix()`

tests/common/util.rs

@@ -625,11 +625,20 @@ impl AtPath {
         // Source:
         // http://stackoverflow.com/questions/31439011/getfinalpathnamebyhandle-without-prepended
         let prefix = "\\\\?\\";
+        // FixME: replace ...
+        #[allow(clippy::manual_strip)]
         if s.starts_with(prefix) {
             String::from(&s[prefix.len()..])
         } else {
             s
         }
+        // ... with ...
+        // if let Some(stripped) = s.strip_prefix(prefix) {
+        //     String::from(stripped)
+        // } else {
+        //     s
+        // }
+        // ... when using MSRV with stabilized `strip_prefix()`
     }
 }