This PR improves the behavior of resetting a column's size by
double-clicking on its column handle. We now shrink/grow to the side
that has more leftover/additional space.
We also improved the below
1. dragging was a couple of pixels off to the left because we didn't
take the column handle’s width into account.
2. Column dragging now has memory and will shift things to their exact
position when reversing a drag before letting the drag handle go.
3. Improved our test infrastructure.
4. Double clicking on a column's header resizes the column
Release Notes:
- N/A
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Co-authored-by: Ben Kunkle <ben@zed.dev>
