🔧 Minor type annotation fix

[codecov[bot]]

Codecov Report

Patch coverage: 66.66% and no project coverage change.

Comparison is base (07e9b7d) 96.07% compared to head (8864e54) 96.07%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #259 +/- ## ======================================= Coverage 96.07% 96.07% ======================================= Files 62 62 Lines 3235 3236 +1 ======================================= + Hits 3108 3109 +1 Misses 127 127 ``` | Flag | Coverage Δ | | |---|---|---| | pytests | `96.07% <66.66%> (+<0.01%)` | :arrow_up: | 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=executablebooks#carryforward-flags-in-the-pull-request-comment) to find out more. | [Impacted Files](https://codecov.io/gh/executablebooks/markdown-it-py/pull/259?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=executablebooks) | Coverage Δ | | |---|---|---| | [markdown\_it/\_compat.py](https://codecov.io/gh/executablebooks/markdown-it-py/pull/259?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=executablebooks#diff-bWFya2Rvd25faXQvX2NvbXBhdC5weQ==) | `87.50% <66.66%> (+1.78%)` | :arrow_up: | 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=executablebooks). 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=executablebooks)

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