Documentation: fix linter errors with TypeScript declarations in Vitest setup instructions

[MaddyGuthridge]

ESLint (with the typescript-eslint plugin) gives a no-undef error without the <T = any> constraint in the type definitions. This PR adds the constraint to help prevent people from getting linting errors from the configuration. TypeScript doesn't seem to be fussed either way, but this should save people a minor annoyance.

What

Add type variable to TypeScript + Vitest setup instructions in the documentation.

Why

Prevent minor annoyances when linting fails for people who use the definitions.

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Latest commit: cfab6a0

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (2483bcc) to head (cfab6a0).
Report is 1 commits behind head on main.

Additional details and impacted files

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[keeganwitt]

I don't have any Vitest experience. Is this still correct? I couldn't find any examples of folks doing it this way (https://github.com/search?q=%22extends+CustomMatchers%3CT+%3D+any%22&type=code).

[MaddyGuthridge]

@keeganwitt that's how I'm doing it in my projects. Without the <T = any>, the linter yells at me.

The reason the search turns up no results is because you've got a typo in your search query. You're hunting for extends CustomMatchers<T = any> when you should be searching for ExpectStatic<T = any> extends CustomMatchers<T>. With the corrected query, you get plenty of results :P

[keeganwitt]

Thanks for the PR! And thanks for clarifying.