Fix this type in TS 4.9

[ChristianMurphy]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and couldn’t find anything (or linked relevant results below)
• If applicable, I’ve added docs and tests

Description of changes

fix this typing in TS4.9

[codecov-commenter]

Codecov Report

Base: 100.00% // Head: 100.00% // No change to project coverage 👍

Coverage data is based on head (ccbf2d3) compared to base (cabbe86).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #304   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           73        73           
  Lines         8486      8487    +1     
=========================================
+ Hits          8486      8487    +1     

Impacted Files	Coverage Δ
packages/remark-lint/index.js	100.00% <100.00%> (ø)

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