fix(linter/plugins): allow fix function to return undefined

[overlookmotel]

Fix types for fix function. Allow it to return undefined, so a pattern where bail out unable to fix is legal:

const rule = {
  create(context) {
    return {
      Identifier(node) {
        context.report({
          message: 'No identifiers!',
          node,
          fix(fixer) {
            if (node.name === 'foo') return; // Can't fix 'foo' for some reason
            return fixer.remove(node);
          },
        });
      },
    };
  },
};

For some reason, this also makes it possible to remove some type assertions.

[overlookmotel]

• fix(linter/plugins): allow fix function to return undefined #14182 👈 (View in Graphite)
• main

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[Copilot]

Pull Request Overview

This PR fixes TypeScript type definitions for the fix function in the linter plugins system to allow returning undefined, enabling a common bail-out pattern where rules can choose not to provide a fix for certain cases.

• Updated the FixFn type to include undefined as a valid return type for individual fixes and the overall function
• Removed type assertion and simplified array conversion logic to handle the expanded type union

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[overlookmotel]

Merge activity

• Sep 27, 10:58 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Sep 27, 10:58 AM UTC: overlookmotel added this pull request to the Graphite merge queue.
• Sep 27, 11:03 AM UTC: Merged by the Graphite merge queue.