useCodeMirror: Updates to the onChange prop are ignored

I strongly recommend to revert 387a0c5b11991841cd40c880bc95cb389de87022 because it has introduced a bug.

It doesn't call the correct onChange, if props.onChange gets changed by the parent component.

But why?

onChange is never updated (current behaviour)

const handleChange = useCallback((value: string, vu: ViewUpdate) => onChange && onChange(value, vu), []);

The handler is updated when onChange updates (correct behaviour)

This has the same behaviour as just calling onCall directly – besides the check for it being falsy.

const handleChange = useCallback((value: string, vu: ViewUpdate) => onChange && onChange(value, vu), [onChange]);

Start at the useCodeMirror implementation and inspect how the onChange callback is created. Reproduce the case where a parent supplies a new onChange prop, then verify that changes invoke the latest callback rather than the original one.