Fix insert_idle lifetimes

[codecov[bot]]

Codecov Report

Base: 89.17% // Head: 89.11% // Decreases project coverage by -0.05% :warning:

Coverage data is based on head (e97d43e) compared to base (99796f9). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #113 +/- ## ========================================== - Coverage 89.17% 89.11% -0.06% ========================================== Files 17 17 Lines 1699 1699 ========================================== - Hits 1515 1514 -1 - Misses 184 185 +1 ``` | Flag | Coverage Δ | | |---|---|---| | macos-latest | `88.58% <100.00%> (-0.08%)` | :arrow_down: | | ubuntu-latest | `87.43% <100.00%> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Smithay#carryforward-flags-in-the-pull-request-comment) to find out more. | [Impacted Files](https://codecov.io/gh/Smithay/calloop/pull/113?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Smithay) | Coverage Δ | | |---|---|---| | [src/loop\_logic.rs](https://codecov.io/gh/Smithay/calloop/pull/113/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Smithay#diff-c3JjL2xvb3BfbG9naWMucnM=) | `89.36% <100.00%> (ø)` | | | [src/sys/mod.rs](https://codecov.io/gh/Smithay/calloop/pull/113/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Smithay#diff-c3JjL3N5cy9tb2QucnM=) | `90.75% <0.00%> (-0.85%)` | :arrow_down: | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Smithay). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Smithay)

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