Clear and concise description of the problem

According to @bradzacher in typescript-eslint/typescript-eslint#8576 (comment) the current typing of the method is flawed. As the current void part of the method would indicate that you shouldn't care about the result.

Suggested solution

Change the return signature of onConsoleLog to false | undefined or boolean | undefined.

The later variant especially would allow for ternaries or simple return expressions like:

onConsoleLog(type) {
  return type != 'stderr';
}

Alternative

No response

Additional context

https://vitest.dev/config/#onconsolelog

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.