Fix clippy

[codecov[bot]]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (1158370) 81.42% compared to head (962cf27) 81.84%. Report is 2 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #878 +/- ## ========================================== + Coverage 81.42% 81.84% +0.41% ========================================== Files 20 20 Lines 3516 3514 -2 ========================================== + Hits 2863 2876 +13 + Misses 653 638 -15 ``` | [Files](https://app.codecov.io/gh/servo/rust-url/pull/878?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=servo) | Coverage Δ | | |---|---|---| | [idna/src/uts46.rs](https://app.codecov.io/gh/servo/rust-url/pull/878?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=servo#diff-aWRuYS9zcmMvdXRzNDYucnM=) | `94.17% <100.00%> (-0.02%)` | :arrow_down: | | [url/src/parser.rs](https://app.codecov.io/gh/servo/rust-url/pull/878?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=servo#diff-dXJsL3NyYy9wYXJzZXIucnM=) | `81.70% <100.00%> (+0.23%)` | :arrow_up: | | [url/src/lib.rs](https://app.codecov.io/gh/servo/rust-url/pull/878?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=servo#diff-dXJsL3NyYy9saWIucnM=) | `75.53% <0.00%> (+1.46%)` | :arrow_up: | ... and [2 files with indirect coverage changes](https://app.codecov.io/gh/servo/rust-url/pull/878/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=servo)

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