Modifier key for bypassing smooth node mode

[Ingolf]

I love love love using smooth nodes mode with the pen tool, but could really use a modifier key for bypassing it just for a second for drawing a straight line and a cusp node.

[VectorStyler]

@Ingolf This already exists, but there isn't much room left for modifiers, so this was unassigned.
In Preferences -> Modifiers, find the "Swap Smooth Pen Clicking" (could be in the All list), and assign a key.