Prevent merge conflicts upfront by highlighting changes of other open PRs/pushed branches

Hi, 

recently we caused a merge hell for each other in our Team. Not the first time, and likely not the last time.

When discussing, I got the Idea that it would have been preventable, if we would have known upfront, that there are changes on a PR, that touches the same code.

This would be a really nice feature IMHO! 

I imagine just some highlighting on the left, that indicates if there are changes to the same lines on a PR or on a pushed branch.

Would this be feasable?

Best regards