Auto merge of #11190 - mrmiywj:Root-tidy-checker, r=jdm

add &Root<T> checker

Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data:
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #11137  (github issue number if applicable).

Either:
- [X] There are tests for these changes OR
- [ ] These changes do not require tests because _____

Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process.

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python/tidy/servo_tidy_tests/rust_tidy.rs

@@ -36,7 +36,7 @@ impl test {
         }
     }
 
-    fn test_fun2(y : &String, z : &Vec<f32>) -> f32 {
+    fn test_fun2(y : &String, z : &Vec<f32>, r: &Root<isize>) -> f32 {
         let x = true;
         x
             && x;