CJK character conversion issue

[askvortsov1]

Thank you so much for all the recent updates, undo/redo are working very well, and the extension API is quite nice!

Our users have reported an issue inputting / converting CJK characters: https://discuss.flarum.org/d/26472-i-cant-type-chinese-in-beta16. Of the top of my head, a guess would be that the issue could have something to do with input events being emitted before the input is actually applied; that could cause the input system's character substitution to happen too early, and be immediately undone by the internals of the mdarea state management system. That's just pure speculation on my part though.

[JohnNiang]

May influenced by: https://github.com/jahudka/mdarea/blob/5369c6c2c0ce33bcc0f03420af693b509f2f2d8b/src/utils/dom.ts#L88