Expose Yjs -> Slate / Slate -> Yjs function transformations

[stedabee]

Hello @BitPhinix ,

First of all, I just want to say thank you for the work you've done. It saves most of us a lot of time and effort trying to translate and sync data between slate and yjs.
I find myself in a position where I have to do some extra data manipulation on the yjs side, to translate some events and extract some data from them.
I couldn't find a way to obtain the slate translated events from YjsEditor, so I am wondering if it's possible to expose some of the core functions related to translation from slate -> yjs and yjs -> slate.
If this is fine with you, I can hapily help with a PR.

Thanks and looking forward to help if needed!
Daniel