Update editor element to use mouse regions instead of dispatch event for mouse events
Fix bug in presenter where mouse region handlers were stored on click and called instead of more up to date handlers from subsequent renders
Changed MouseRegion to require discriminants in all cases
Add scroll wheel event to MouseRegion
Polished a bunch of dock inconsistencies
Co-Authored-By: Mikayla Maki <mikayla@zed.dev>
This gives us a chance to highlight a real-world scenario that a lot
of our users will want to use, as well as showcasing the special
`{buffer_path}` argument.