a97a9b33fc
Updates the documentation for the [`matchesGoldenFile`](https://api.flutter.dev/flutter/flutter_test/matchesGoldenFile.html) comparator. The documentation currently references the abstract class [`GoldenFileComparator`](https://api.flutter.dev/flutter/flutter_test/GoldenFileComparator-class.html) "as the backend for this matcher", however I believe it should instead reference to [`goldenFileComparator`](https://api.flutter.dev/flutter/flutter_test/goldenFileComparator.html) that also clearly states in its documentation that it is "This comparator is used as the backend for [matchesGoldenFile](https://api.flutter.dev/flutter/flutter_test/matchesGoldenFile.html).". Knowledge about [`goldenFileComparator`](https://api.flutter.dev/flutter/flutter_test/goldenFileComparator.html) is useful for Flutter developers since it is required when trying to set their own custom comparator, and there is currently no reference to it within the [`matchesGoldenFile`](https://api.flutter.dev/flutter/flutter_test/matchesGoldenFile.html). The abstract class [`GoldenFileComparator`](https://api.flutter.dev/flutter/flutter_test/GoldenFileComparator-class.html) is still being referenced within the second suggestion. #76337, precisely https://github.com/flutter/flutter/issues/76337#issuecomment-2172941109