servo: Merge #11329 - Report use statements that use {} with only one entry (from c-rhodes:11320); r=jdm

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 --faster` does not report any errors
- [X ] These changes fix #11320  (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.

Source-Repo: https://github.com/servo/servo
Source-Revision: 2f9796fa696e9514280777398467696dd4f004b3

servo/python/tidy/servo_tidy_tests/rust_tidy.rs

@@ -7,6 +7,7 @@ use azure::azure_hl::{AntialiasMode, Color,
 ColorPattern, CompositionOp};
 use euclid::size::Size2D;
 use azure::azure::AzIntSize;
+use azure::azure::{AzIntSize};
 
 use std;
 

servo/python/tidy/servo_tidy_tests/test_tidy.py

@@ -53,6 +53,7 @@ class CheckTidiness(unittest.TestCase):
         self.assertEqual('use statement spans multiple lines', errors.next()[2])
         self.assertEqual('missing space before }', errors.next()[2])
         self.assertTrue('use statement is not in alphabetical order' in errors.next()[2])
+        self.assertEqual('use statement contains braces for single import', errors.next()[2])
         self.assertEqual('encountered whitespace following a use statement', errors.next()[2])
         self.assertTrue('mod declaration is not in alphabetical order' in errors.next()[2])
         self.assertEqual('mod declaration spans multiple lines', errors.next()[2])