fix: Ignoring result from pure array method

[odaysec]

fix issue must actually incorporate this.scope into the res array when serializing. Since Array.prototype.concat returns a new array, we should either assign that result back to res or, more simply, use res.push(this.scope) which mutates res in place. This maintains existing functionality and type shape (an array starting with "config" and the key, optionally followed by scope).

The best minimal fix is within Config.serialize in src/style-spec/expression/definitions/config.ts: change the line res.concat(this.scope); to res.push(this.scope);. This requires no new imports or additional helper methods. Alternatively, res = res.concat(this.scope); would also work, but push is simpler and clearer that res is being mutated. No other parts of the file need to be changed.

Specifically:

• In serialize(), at the if (this.scope) { ... } block, replace the concat call with push.
• Ensure the function still returns res as before.

Launch Checklist

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