InfoView popups need scrollability

[lovettchris]

Some large markdown comment blocks require scrolling like this, which you will see in the editor tips:

Today the infoview will render large popups off the bottom or off the top of the infoview:

or

and the vertical size will be infinite with no nested scrollbar inside the tip. I think a fixed max vertical height with scrollbars when needed would be nicer especially because of the flip() limitations in Popper v2.x mentioned in #207

[lovettchris]

@Vtec234 says
Fwiw, I tried floating-ui in the infoview a while ago and it was completely not working. However it looks like they have added a whole lot of utilities since then and presumably fixed bugs, so it might be worth giving another go, if we can reproduce all existing functionality using it (it would be a large change).

[lovettchris]

The flip logic is completely lacking any concept of "best" orientation based on "minimal offscreen" amounts. Instead it is a binary switch, if "bottom" results in any amount off the bottom then don't use it which is a not the best algorithm for large hover tips, and turns out off the bottom in the InfoView is fine because the InfoView itself is scrollable, so it's easy to read the hover tip with some vertical scrolling, off the top is much worse because the InfoView scrollbar won't go negative.

The flip() implementation in Popper v2 is also impossible to replace as far as I can tell, but I've noticed Popper seems to be replaced now by https://github.com/floating-ui/floating-ui which looks much better because it gives you much more control over the middleware (e.g. flip function etc). It also claims to be smaller and lighter so we should be able to implement a more InfoView friendly flip algorithm very easily.