Allow rules to have the fix function

There are rules which we could potentially enable fixers for.

Imagine if the rule had an API such as...

const someRule = {
  check: async (filename, options) => {
    // make an errors array
    return errors;
  }, 
  fix: async (errors, options) => {
    // do some stuff to fix the error
  }
}

export const someRule;

This is similar to how manypkg works here...

And how eslint rules work as well such as here...

Start by reviewing the existing rule API and the path that runs rule checks, then compare the proposed shape with the linked manypkg and ESLint examples. Define how a rule exposes a fixer, how errors and options are passed, and how the command invokes it; done means eligible rules can fix their reported errors without breaking check-only behavior.