fix: codemirror does not vanish anymore on hot reload

[felixroos]

when saving certain files, for example superdough.mjs, the codemirror editor would just vanish.
It seems the hot reloading clears the #code element (Repl.jsx) without deleting the refs, so init won't be called again.
Luckily, there is an API for vite to hook into hot reloading life cycle: https://vitejs.dev/guide/api-hmr#hot-dispose-cb

I managed to at least clear the refs and stop the previous repl, so it will be recreated when the #code ref fires again.
I am not sure if it's even possible to hot swap the editor without loosing the context. maybe it is but maybe it's not worth the hassle. @daslyfe any idea? how is this related to #892 ?

[daslyfe]

Sorry, forgot to respond to this one. iirc 892 was hot reloading failing to run on the newest pnpm version, not just the editor.