Handle beforeinput events

[marijnh]

Browsers are starting to ship these events, and they can be useful for some things, like detecting an undo/redo from the menu. Not sure yet whether this belongs in the core or in a plugin.

In a perfect future, a lot of keybindings could be replaced by binding input types, but I expect it'll be a while before any browsers are that far.

[holtwick]

Starting with iOS 13 it is possible to trigger UNDO with 3 finger gestures like 3-finger-swipe to the left or double tapping with 3 fingers. This native UNDO does not work well with ProseMirror. I wrote a plugin for TipTap solving the issue for me based on discussions on the ProseMirror discussion list. But maybe something like this should get into the core of ProseMirror? See ueberdosis/tiptap#468

[marijnh]

Putting code like this into the history package and exporting it as a separate plugin might be a good idea. I think it's too terrible a hack to enable by default, but it might be useful to a lot of people.