Fix sequence widgets

[krysros]

Example

Before

After

[stevepiercy]

@krysros thank you for your contribution!

It will be a while until I can review this.

Meanwhile deformdemo needs to be updated so the functional tests pass. Please let me know if you need help to get that running locally. We have pretty good docs to help you get started in https://github.com/Pylons/deform/blob/main/contributing.md

This also needs a note in CHANGES.txt.

Side note, main needs a lot more work to comply with Bootstrap 4.x before this can go in. I might also skip 4 and go straight to 5.

[krysros]

I work on Windows, so running functional tests will not be an easy task. Maybe I'll try it on a virtual machine.

For now I'm pretty sure that to fix this conflict it is enough to change "panel-heading" class to "card-header" in this line:

https://github.com/Pylons/deformdemo/blob/f124a2bc846c9b66510255065f2e07fb7a87a676/deformdemo/test.py#L3374

[krysros]

This is what it looks like after the changes. We can go back to the icons in Bootstrap 5.