Fix answer field editing

[psfinaki]

For some reason, cursor in the answer field behaves weirdly:

1. Type something there, e.g. answer
2. Move cursor in the middle of the word, i.e. between s and w
3. Type a letter or remove one
4. Cursor moves to the end of the word

This should be fixed, this is even more inconvenient from mobile.

[psfinaki]

The whole thing is not as trivial as expected.

It is related to some internal React rendering mechanisms I am not very good at. The issue is common, described e.g. here or here. Basically, cursor reset is a side effect of changing the input value programmatically.

The above links have some workarounds - none of them are trivial and require diving into JS. JavaScript generated by Fable is again a separate topic for me, so I have decided to postpone the issue and have another take in some time.