`<bmx-step>`

One step of a bmx-stepper.

A step is an ordinary element holding ordinary content. It shows while it is the current step.

Shown as optional; a linear stepper lets it be passed over.

The icon replaces the step's number in its circle.

A step is only ever inside a bmx-stepper: it carries the label the step list is drawn from, and the stepper decides which one is showing.