ui: Add animation support for the edited/moved marker.
This is a sequel to #762 that animates the swipe gesture.
Comparisons:
| Collapsed | Expanded |
|---|---|
The appearances of the markers can be checked in the comparisons table above.
Incorporating @chrisbobbe 's comment, we animate the marker from the start state to the end state as follows:
| margin left | margin right | paddings (horizontal symmetric) | distance between marker text and icon | |
|---|---|---|---|---|
| Collapsed | 5px | 3px | 0px | 0px |
| Expanded | 13px | 3px | 3px | 5px |
where the paddings are the distances "between the left edge of the rounded-rectangle and 'Edited'" and "between the icon and the right edge of the rounded-rectangle", the margins are the distance between the rectangle to the left of the screen and to the message content, respectively.
Rebased since #762 has been merged. We will need to get back to this later to investigate alternatives to LayoutBuilder.
My review is next, I think, right? I've just added "maintainer review" so I don't lose track of it.
Yeah, this is not ready for review yet, but I will let you know once it is.
Marked as draft because that makes it easier to remember (particularly when looking at a list of PRs) which PRs have become ready for review :slightly_smiling_face: