* Closes no issue, I just needed this for an app and figured it could be
useful.
* [x] I have followed the instructions in the PR template
This PR adds an `overline` option for `egui_extras::TableRow`, which is
useful for visually grouping rows. The overline consumes no layout
space.
A screenshot of the demo app, showing every 7th row getting an overline.
<img width="704" alt="Screenshot 2025-01-25 at 14 40 08"
src="https://github.com/user-attachments/assets/9ccbee3d-296d-4afd-9290-c669e4ede1c0"
/>
---------
Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
36e007bd8c
