FeatureRequest: check manual changes on page before overwriting it

[no-one2k]

Case:

1. we made jupyter notebook and linked it to confluence page
2. we commited it for the first time, so now page and notebook are synchronized
3. someone manually modified page
4. we modified notebook and commited it => manual changes will be lost (that's probably okay) and nobody will know about it (that's not okay)

So it would be nice to check before commiting notebook if page was manually changed and ask a confirmation.

[sancau]

Actully the manual changes won't be lost completely as there is version history in Confluence intself.
Still, I think that's a nice thing to have (a warning on push). At the moment we are limited by the nbconflux library in our interaction with Confluence and I suppose it doesn't have such feature.

I'm going to check out if there's a relatively easy and straightforward way to do it.